Safety Issues and Improvement Measures of Ni-Rich Layered Oxide Cathode Materials for Li-Ion Batteries

Abstract

Ni-rich layered oxide cathode materials hold great promise for enhancing the energy density of lithium-ion batteries (LIBs) due to their impressive specific capacity. However, the chemical and structural stability issues associated with the materials containing a high Ni content have emerged as a primary safety concern, particularly in the context of traction batteries for electric vehicles. Typically, when these materials are in a highly charged state, their metastable layered structure and highly oxidized transition metal ions can trigger detrimental phase transitions. This leads to the generation of oxygen gas and the degradation of the material’s microstructure, including the formation of cracks, which can promote the interactions between Ni-rich materials and electrolytes, further generating flammable gases. Consequently, various strategies have been devised at the material level to mitigate potential safety hazards. This review begins by providing an in-depth exploration of the sources of instability in Ni-rich layered oxides, drawing from their crystal and electronic structures, and subsequently outlines the safety issues that arise as a result. Subsequently, it delves into recent advancements and approaches aiming at modifying Ni-rich cathode materials and electrolytes to enhance safety. The primary objective of this review is to offer a concise and comprehensive understanding of why Ni-rich cathode materials are susceptible to safety incidents and to present potential methods for improving the safety of Ni-rich cathode materials in high-density LIBs.

Graphical Abstract

Safety risk origin of Ni-rich cathode materials, potential safety issues, and possible measures to improve safety are summarized.

Keywords

Lithium-ion battery / Ni-rich layered oxide / Cathode material / Battery safety / Thermal runaway

References

[1] BloombergNEF: EVO Report 2023. 2023 Bloomberg Finance L.P. https://about.bnef.com/electric-vehicle-outlook/ (2023). Accessed 20 Sept 2023

[2] Reiner K. Lithium-Ion Batteries: Basics and Applications, 2018, Berlin, Heidelberg, Springer

[3] Shao ZP, Liu YF, Chen YB, et al.. Significantly improving energy density of cathode for lithium ion batteries: the effect of Li-Zr composite oxides coating on LiNi_0.6Co_0.2Mn_0.2O₂. Ionics, 2020, 26: 1173-1180

[4] Das S. Highly concentrated nitrile functionalized disiloxane-LiFSI based non-flammable electrolyte for high energy density Li metal battery. J. Electroanal. Chem., 2020, 879: 114794

[5] Hyung YE, Vissers DR, Amine K. Flame-retardant additives for lithium-ion batteries. J. Power. Sources, 2003, 119(120/121): 383-387

[6] Myung ST, Maglia F, Park KJ, et al.. Nickel-rich layered cathode materials for automotive lithium-ion batteries: achievements and perspectives. ACS Energy Lett., 2017, 2: 196-223

[7] Dahn JR, von Sacken U, Michal CA. Structure and electrochemistry of Li_1±yNiO₂ and a new Li₂NiO₂ phase with the Ni(OH)₂ structure. Solid State Ion., 1990, 44: 87-97

[8] Granholm, J.M.: National Blueprint for Lithium Batteries 2021–2030. U.S. Department of Energy. https://www.energy.gov/sites/default/files/2021-06/FCAB%20National%20Blueprint%20Lithium%20Batteries%200621_0.pdf (2021). Accessed 20 Sept 2023

[9] National Administration for Market Regulation and National Standardization Administration of China: Electric vehicles traction battery safety requirements. Ministry of Industry and Information Technology. https://openstd.samr.gov.cn/bzgk/gb/newGbInfo?hcno=F15853431BDDCCEDD525298F719A9254 (2020). Accessed 20 Sept 2023

[10] Ministry of Industry and Information Technology: Three Mandatory National Standards for Electric Vehicles were Officially Released. Department Government Affairs, China Government Network. http://www.gov.cn/xinwen/2020-05/14/content_5511415.htm (2020). Accessed 20 Sept 2023

[11] China Center for Information Industry Development (CCID): White Paper on the Development of Lithium Ion Battery Industry (2021 Edition). Ministry of Industry and Information Technology of China. https://www.ccidgroup.com/info/1044/33820.htm (2021). Accessed 20 Sept 2023

[12] National Manufacturing Power Construction Strategy Advisory Committee: Technical Roadmap for Key Areas of “Made in China 2025”. (2015)

[13] CATL: CTP Technology. http://www.wnevc.com/CN/EShow/49.html (2023). Accessed 21 Sept 2023

[14] Tu SB, Lu ZH, Zheng MT, et al.. Single-layer-particle electrode design for practical fast-charging lithium-ion batteries. Adv. Mater., 2022, 34: 2202892

[15] Gervillié-Mouravieff C, Albero Blanquer L, Alphen C, et al.. Unraveling SEI formation and cycling behavior of commercial Ni-rich NMC Li-ion pouch cells through operando optical characterization. J. Power. Sources, 2023, 580: 233268

[16] Ku K, Son SB, Gim J, et al.. Understanding the constant-voltage fast-charging process using a high-rate Ni-rich cathode material for lithium-ion batteries. J. Mater. Chem. A, 2022, 10: 288-295

[17] Croy JR, Long BR, Balasubramanian M. A path toward cobalt-free lithium-ion cathodes. J. Power. Sources, 2019, 440: 227113

[18] Seenivasan M, Yang CC, Wu SH, et al.. Using a Couette-Taylor vortex flow reactor to prepare a uniform and highly stable Li[Ni_0.80Co_0.15Al_0.05]O₂ cathode material. J. Alloys Compd., 2021, 857: 157594

[19] Delmas C, Fouassier C, Hagenmuller P. Structural classification and properties of the layered oxides. Phys. B+C, 1980, 99: 81-85

[20] de Biasi L, Schwarz B, Brezesinski T, et al.. Chemical, structural, and electronic aspects of formation and degradation behavior on different length scales of Ni-rich NCM and Li-rich HE-NCM cathode materials in Li-ion batteries. Adv. Mater., 2019, 31: e1900985

[21] Li W, Reimers JN, Dahn JR. In situ X-ray diffraction and electrochemical studies of Li_1−xNiO₂. Solid State Ion., 1993, 67: 123-130

[22] Dyer LD, Borie BSJr, Smith GP. Alkali metal-nickel oxides of the type MNiO₂. J. Am. Chem. Soc., 1954, 76: 1499-1503

[23] Dahn JR, Fuller EW, Obrovac M, et al.. Thermal stability of Li_xCoO₂, Li_xNiO₂ and λ-MnO₂ and consequences for the safety of Li-ion cells. Solid State Ion., 1994, 69: 265-270

[24] Zhang Z, Fouchard D, Rea JR. Differential scanning calorimetry material studies: implications for the safety of lithium-ion cells. J. Power. Sources, 1998, 70: 16-20

[25] Arai H, Okada S, Sakurai Y, et al.. Reversibility of LiNiO₂ cathode. Solid State Ion., 1997, 95: 275-282

[26] Lu ZH, MacNeil DD, Dahn JR. Layered cathode materials Li[Ni_xLi_(1/3–2x/3)Mn_(2/3–x/3)]O₂ for lithium-ion batteries. Electrochem. Solid-State Lett., 2001, 4: A191

[27] Ohzuku T, Ueda A, Nagayama M, et al.. Comparative study of LiCoO₂, LiNiCoO₂ and LiNiO₂ for 4 volt secondary lithium cells. Electrochim. Acta, 1993, 38: 1159-1167

[28] Yin SY, Deng WT, Chen J, et al.. Fundamental and solutions of microcrack in Ni-rich layered oxide cathode materials of lithium-ion batteries. Nano Energy, 2021, 83: 105854

[29] Chang KK, Hallstedt B, Music D. Thermodynamic description of the LiNiO₂-NiO₂ pseudo-binary system and extrapolation to the Li(Co, Ni)_O2-(Co, Ni₎O2 system. Calphad, 2012, 37: 100-107

[30] Molenda J, Marzec J. Functional cathode materials for li-ion batteries. Part III: potential cathode materials LixNi_1−y−zCo_yMn_zO₂ and LiMn₂O₄. Funct. Mater. Lett., 2009, 2: 1-7

[31] Liang CP, Kong FT, Longo RC, et al.. Unraveling the origin of instability in Ni-rich LiNi_1–2xCo_xMn_xO₂ (NCM) cathode materials. J. Phys. Chem. C, 2016, 120: 6383-6393

[32] Noh HJ, Youn S, Yoon CS, et al.. Comparison of the structural and electrochemical properties of layered Li[Ni_xCo_yMn_z]O₂ (x = 1/3, 0.5, 0.6, 0.7, 0.8 and 0.85) cathode material for lithium-ion batteries. J. Power. Sources, 2013, 233: 121-130

[33] Dixit M, Markovsky B, Schipper F, et al.. Origin of structural degradation during cycling and low thermal stability of Ni-rich layered transition metal-based electrode materials. J. Phys. Chem. C, 2017, 121: 22628-22636

[34] Ohzuku T, Ueda A, Nagayama M. Electrochemistry and structural chemistry of LiNiO₂ (R3m) for 4 volt secondary lithium cells. J. Electrochem. Soc., 1993, 140: 1862-1870

[35] MacNeil DD, Lu Z, Dahn JR. Structure and electrochemistry of Li[Ni_xCo_1–2xMn_x]O₂ (0 ⩽ x ⩽ 1/2). J. Electrochem. Soc., 2002, 149: A1332

[36] Liang C, Jiang LH, Wei ZS, et al.. Insight into the structural evolution and thermal behavior of LiNi_0.8Co_0.1Mn_0.1O₂ cathode under deep charge. J. Energy Chem., 2022, 65: 424-432

[37] Liu LH, Li MC, Chu LH, et al.. Layered ternary metal oxides: performance degradation mechanisms as cathodes, and design strategies for high-performance batteries. Prog. Mater. Sci., 2020, 111: 100655

[38] Yoshio M, Noguchi H, Itoh JI, et al.. Preparation and properties of LiCo_yMn_xNi_1−x−yO₂ as a cathode for lithium ion batteries. J. Power Sources, 2000, 90: 176-181

[39] Zhang S, Ma J, Hu ZL, et al.. Identifying and addressing critical challenges of high-voltage layered ternary oxide cathode materials. Chem. Mater., 2019, 31: 6033-6065

[40] Lu Y, Zhang YD, Zhang Q, et al.. Recent advances in Ni rich layered oxide particle materials for lithium-ion batteries. Particuology, 2020, 53: 1-11

[41] Tallman KR, Wheeler GP, Kern CJ, et al.. Nickel-rich nickel manganese cobalt (NMC622) cathode lithiation mechanism and extended cycling effects using operando X-ray absorption spectroscopy. J. Phys. Chem. C, 2021, 125: 58-73

[42] Liu X, Xu GL, Yin L, et al.. Probing the thermal-driven structural and chemical degradation of Ni-rich layered cathodes by Co/Mn exchange. J. Am. Chem. Soc., 2020, 142: 19745-19753

[43] Wang XX, Ding YL, Deng YP, et al.. Ni-rich/Co-poor layered cathode for automotive Li-ion batteries: promises and challenges. Adv. Energy Mater., 2020, 10: 1903864

[44] Choi J, Manthiram A. Role of chemical and structural stabilities on the electrochemical properties of layered LiNi_1∕3Mn_1∕3Co_1∕3O₂ cathodes. J. Electrochem. Soc., 2005, 152: A1714

[45] Kim JM, Chung HT. The first cycle characteristics of Li[Ni_1/3Co_1/3Mn_1/3]O₂ charged up to 4.7 V. Electrochim. Acta, 2004, 49: 937-944

[46] Molenda J, Milewska A. Structural and transport properties of Li_xNi_1−y−zCo_yMn_zO₂ cathode materials. J. Power Sources, 2009, 194: 88-92

[47] Shaju KM, Subba Rao GV, Chowdari BVR. Performance of layered Li(Ni_1/3Co_1/3Mn_1/3)O₂ as cathode for Li-ion batteries. Electrochim. Acta, 2002, 48: 145-151

[48] Liang C, Zhang WH, Wei ZS, et al.. Transition-metal redox evolution and its effect on thermal stability of LiNi_xCo_yMn_zO₂ based on synchrotron soft X-ray absorption spectroscopy. J. Energy Chem., 2021, 59: 446-454

[49] Sun HH, Choi W, Lee JK, et al.. Control of electrochemical properties of nickel-rich layered cathode materials for lithium ion batteries by variation of the manganese to cobalt ratio. J. Power Sources, 2015, 275: 877-883

[50] Goodenough JB, Park KS. The Li-ion rechargeable battery: a perspective. J. Am. Chem. Soc., 2013, 135: 1167-1176

[51] Radin MD, Hy S, Sina M, et al.. Narrowing the gap between theoretical and practical capacities in Li-ion layered oxide cathode materials. Adv. Energy Mater., 2017, 7: 1602888

[52] Kuo LY, Guillon O, Kaghazchi P. Origin of structural phase transitions in Ni-rich Li_xNi_0.8Co_0.1Mn_0.1O₂ with lithiation/delithiation: a first-principles study. ACS Sustain. Chem. Eng., 2021, 9: 7437-7446

[53] Li LZ, Self EC, Darbar D, et al.. Hidden subsurface reconstruction and its atomic origins in layered oxide cathodes. Nano Lett., 2020, 20: 2756-2762

[54] Chen JX, Zhang XQ, Li BQ, et al.. The origin of sulfuryl-containing components in SEI from sulfate additives for stable cycling of ultrathin lithium metal anodes. J. Energy Chem., 2020, 47: 128-131

[55] Luo XH, Xing LD, Vatamanu J, et al.. Inhibiting manganese (II) from catalyzing electrolyte decomposition in lithium-ion batteries. J. Energy Chem., 2022, 65: 1-8

[56] Xie Q, Cui ZH, Manthiram A. Unveiling the stabilities of nickel-based layered oxide cathodes at an identical degree of delithiation in lithium-based batteries. Adv. Mater., 2021, 33: 2100804

[57] Bang HJ, Joachin H, Yang H, et al.. Contribution of the structural changes of LiNi_0.8Co_0.15Al_0.05O₂ cathodes on the exothermic reactions in Li-ion cells. J. Electrochem. Soc., 2006, 153: A731

[58] Ju SH, Jang HC, Kang YC. Al-doped Ni-rich cathode powders prepared from the precursor powders with fine size and spherical shape. Electrochim. Acta, 2007, 52: 7286-7292

[59] Kostecki R, McLarnon F. Local-probe studies of degradation of composite LiNi_0.8Co_0.15Al_0.05O₂ cathodes in high-power lithium-ion cells. Electrochem. Solid-State Lett., 2004, 7: A380

[60] Weaving JS, Coowar F, Teagle DA, et al.. Development of high energy density Li-ion batteries based on LiNi_1−x−yCo_xAl_yO₂. J. Power Sources, 2001, 97: 733-735

[61] Biensan P, Simon B, Pérès JP, et al.. On safety of lithium-ion cells. J. Power Sources, 1999, 81–82: 906-912

[62] Wang B, Zhang FL, Zhou XN, et al.. Which of the nickel rich NCM and NCA is structurally superior as a cathode material for lithium-ion batteries?. J. Mater. Chem. A, 2021, 9: 13540-13551

[63] Chebiam RV, Prado F, Manthiram A. Structural instability of delithiated Li_1–xNi_1–yCo_yO₂ cathodes. J. Electrochem. Soc., 2001, 148: A49

[64] Belharouak I, Lu WQ, Vissers D, et al.. Safety characteristics of Li(Ni_0.8Co_0.15Al_0.05)O₂ and Li(Ni_1/3Co_1/3Mn_1/3)O₂. Electrochem. Commun., 2006, 8: 329-335

[65] Lv Y, Huang SF, Zhao YF, et al.. A review of nickel-rich layered oxide cathodes: synthetic strategies, structural characteristics, failure mechanism, improvement approaches and prospects. Appl. Energy, 2022, 305: 117849

[66] Zheng JX, Teng GF, Xin C, et al.. Role of superexchange interaction on tuning of Ni/Li disordering in layered Li(Ni_xMn_yCo_z)O₂. J. Phys. Chem. Lett., 2017, 8: 5537-5542

[67] Lin F, Markus IM, Nordlund D, et al.. Surface reconstruction and chemical evolution of stoichiometric layered cathode materials for lithium-ion batteries. Nat. Commun., 2014, 5: 1-9

[68] Liu W, Oh P, Liu XE, et al.. Nickel-rich layered lithium transition-metal oxide for high-energy lithium-ion batteries. Angew. Chem. Int. Ed., 2015, 54: 4440-4457

[69] Liang CP, Longo RC, Kong FT, et al.. Obstacles toward unity efficiency of LiNi_1−2xCo_xMn_xO₂ (x = 0–1/3) (NCM) cathode materials: insights from ab initio calculations. J. Power Sources, 2017, 340: 217-228

[70] Jung SK, Gwon H, Hong J, et al.. Understanding the degradation mechanisms of LiNi_0.5Co_0.2Mn_0.3O₂ cathode material in lithium ion batteries. Adv. Energy Mater., 2014, 4: 1300787

[71] Lee J, Urban A, Li X, et al.. Unlocking the potential of cation-disordered oxides for rechargeable lithium batteries. Science, 2014, 343: 519-522

[72] Hu JT, Wang QC, Wu BB, et al.. Fundamental linkage between structure, electrochemical properties, and chemical compositions of LiNi_1−x−yMn_xCo_yO₂ cathode materials. ACS Appl. Mater. Interfaces, 2021, 13: 2622-2629

[73] Orlova ED, Savina AA, Abakumov SA, et al.. Comprehensive study of Li⁺/Ni²⁺ disorder in Ni-rich NMCs cathodes for Li-ion batteries. Symmetry, 2021, 13: 1628

[74] Yang CK, Shao RW, Wang Q, et al.. Bulk and surface degradation in layered Ni-rich cathode for Li ions batteries: defect proliferation via chain reaction mechanism. Energy Storage Mater., 2021, 35: 62-69

[75] Liang LW, Zhang WH, Zhao F, et al.. Surface/interface structure degradation of Ni-rich layered oxide cathodes toward lithium-ion batteries: fundamental mechanisms and remedying strategies. Adv. Mater. Interfaces, 2020, 7: 1901749

[76] Ryu HH, Park KJ, Yoon CS, et al.. Capacity fading of Ni-rich Li[Ni_xCo_yMn_1–x–y]O₂ (0.6 ⩽ x ⩽ 0.95) cathodes for high-energy-density lithium-ion batteries: bulk or surface degradation?. Chem. Mater., 2018, 30: 1155-1163

[77] Watanabe S, Kinoshita M, Hosokawa T, et al.. Capacity fade of LiAl_yNi_1−x−yCo_xO₂ cathode for lithium-ion batteries during accelerated calendar and cycle life tests (surface analysis of LiAl_yNi_1−x−yCo_xO₂ cathode after cycle tests in restricted depth of discharge ranges). J. Power Sources, 2014, 258: 210-217

[78] Xu X, Huo H, Jian JY, et al.. Radially oriented single-crystal primary nanosheets enable ultrahigh rate and cycling properties of LiNi_0.8Co_0.1Mn_0.1O₂ cathode material for lithium-ion batteries. Adv. Energy Mater., 2019, 9: 1803963

[79] Yan PF, Zheng JM, Gu M, et al.. Intragranular cracking as a critical barrier for high-voltage usage of layer-structured cathode for lithium-ion batteries. Nat. Commun., 2017, 8: 14101

[80] Kim NY, Yim T, Song JH, et al.. Microstructural study on degradation mechanism of layered LiNi_0.6Co_0.2Mn_0.2O₂ cathode materials by analytical transmission electron microscopy. J. Power Sources, 2016, 307: 641-648

[81] Kleiner K, Melke J, Merz M, et al.. Unraveling the degradation process of LiNi_0.8Co_0.15Al_0.05O₂ electrodes in commercial lithium ion batteries by electronic structure investigations. ACS Appl. Mater. Interfaces, 2015, 7: 19589-19600

[82] Liang LW, Wu C, Sun XF, et al.. Sur-/interface engineering of hierarchical LiNi_0.6Mn_0.2Co_0.2O₂@LiCoPO₄@graphene architectures as promising high-voltage cathodes toward advanced Li ion batteries. Adv. Mater. Interfaces, 2017, 4: 1700382

[83] Su YF, Zhang QY, Chen L, et al.. Stress accumulation in Ni-rich layered oxide cathodes: origin, impact, and resolution. J. Energy Chem., 2022, 65: 236-253

[84] Watanabe S, Kinoshita M, Hosokawa T, et al.. Capacity fading of LiAl_yNi_1−x−yCo_xO₂ cathode for lithium-ion batteries during accelerated calendar and cycle life tests (effect of depth of discharge in charge-discharge cycling on the suppression of the micro-crack generation of LiAl_yNi_1−x−yCo_xO₂ particle). J. Power Sources, 2014, 260: 50-56

[85] Miller DJ, Proff C, Wen JG, et al.. Observation of microstructural evolution in Li battery cathode oxide particles by in situ electron microscopy. Adv. Energy Mater., 2013, 3: 1098-1103

[86] Bareño J, Lei CH, Wen JG, et al.. Local structure of layered oxide electrode materials for lithium-ion batteries. Adv. Mater., 2010, 22: 1122-1127

[87] Yang SY, Shadike Z, Wang WW, et al.. An ultrathin solid-state electrolyte film coated on LiNi_0.8Co_0.1Mn_0.1O₂ electrode surface for enhanced performance of lithium-ion batteries. Energy Storage Mater., 2022, 45: 1165-1174

[88] Lin QY, Guan WH, Zhou JB, et al.. Ni-Li anti-site defect induced intragranular cracking in Ni-rich layer-structured cathode. Nano Energy, 2020, 76: 105021

[89] Zhu J, Sharifi-Asl S, Garcia JC, et al.. Atomic-level understanding of surface reconstruction based on Li[Ni_xMn_yCo_1−x−y]O₂ single-crystal studies. ACS Appl. Energy Mater., 2020, 3: 4799-4811

[90] Jiang M, Danilov DL, Eichel RA, et al.. A review of degradation mechanisms and recent achievements for Ni-rich cathode-based Li-ion batteries. Adv. Energy Mater., 2021, 11: 2103005

[91] Wu F, Liu N, Chen L, et al.. The nature of irreversible phase transformation propagation in nickel-rich layered cathode for lithium-ion batteries. J. Energy Chem., 2021, 62: 351-358

[92] Choi J, Dong L, Yu CY, et al.. Relationship of chemical composition and moisture sensitivity in LiNi_xMn_yCo_1−x−yO₂ for lithium-ion batteries. J. Electrochem. Energy Convers. Stor., 2021, 18: 041009

[93] Xiao XC, Liu ZY, Baggetto L, et al.. Unraveling manganese dissolution/deposition mechanisms on the negative electrode in lithium ion batteries. Phys. Chem. Chem. Phys., 2014, 16: 10398-10402

[94] Nam KW, Bak SM, Hu E, et al.. Combining in situ synchrotron X-ray diffraction and absorption techniques with transmission electron microscopy to study the origin of thermal instability in overcharged cathode materials for lithium-ion batteries. Adv. Funct. Mater., 2013, 23: 1047-1063

[95] Pokle A, Ahmed S, Schweidler S, et al.. In situ monitoring of thermally induced effects in nickel-rich layered oxide cathode materials at the atomic level. ACS Appl. Mater. Interfaces, 2020, 12: 57047-57054

[96] Alvarado J, Wei CX, Nordlund D, et al.. Thermal stress-induced charge and structure heterogeneity in emerging cathode materials. Mater. Today, 2020, 35: 87-98

[97] Xia HY, Liu C, Shen L, et al.. Structure and thermal stability of LiNi_0.8Co_0.15Al_0.05O₂ after long cycling at high temperature. J. Power Sources, 2020, 450: 227695

[98] Wang Y, Ren DS, Feng XN, et al.. Thermal kinetics comparison of delithiated Li[Ni_xCo_yMn_1−x−y]O₂ cathodes. J. Power Sources, 2021, 514: 230582

[99] Lee E, Muhammad S, Kim T, et al.. Tracking the influence of thermal expansion and oxygen vacancies on the thermal stability of Ni-rich layered cathode materials. Adv. Sci., 2020, 7: 1902413

[100] Martinez AC, Grugeon S, Cailleu D, et al.. High reactivity of the nickel-rich LiNi_1−x−yMn_xCo_yO₂ layered materials surface towards H₂O/CO₂ atmosphere and LiPF₆-based electrolyte. J. Power Sources, 2020, 468: 228204

[101] Geng LX, Liu J, Wood III DL, et al.. Probing thermal stability of Li-ion battery Ni-rich layered oxide cathodes by means of operando gas analysis and neutron diffraction. ACS Appl. Energy Mater., 2020, 3: 7058-7065

[102] Ghiji M, Novozhilov V, Moinuddin K, et al.. A review of lithium-ion battery fire suppression. Energies, 2020, 13: 5117

[103] Swiderska-Mocek A, Jakobczyk P, Rudnicka E, et al.. Flammability parameters of lithium-ion battery electrolytes. J. Mol. Liq., 2020, 318: 113986

[104] Hou JX, Feng XN, Wang L, et al.. Unlocking the self-supported thermal runaway of high-energy lithium-ion batteries. Energy Stor. Mater., 2021, 39: 395-402

[105] Jung R, Metzger M, Maglia F, et al.. Chemical versus electrochemical electrolyte oxidation on NMC111, NMC622, NMC811, LNMO, and conductive carbon. J. Phys. Chem. Lett., 2017, 8: 4820-4825

[106] Berkes BB, Jozwiuk A, Vraar M, et al.. Online continuous flow differential electrochemical mass spectrometry with a realistic battery setup for high-precision, long-term cycling tests. Anal. Chem., 2015, 87: 5878-5883

[107] Kleiner K, Ehrenberg H. Challenges considering the degradation of cell components in commercial lithium-ion cells: a review and evaluation of present systems. Topics Curr. Chem., 2017, 375: 54

[108] Liao ZH, Zhang S, Zhao YK, et al.. Experimental evaluation of thermolysis-driven gas emissions from LiPF₆-carbonate electrolyte used in lithium-ion batteries. J. Energy Chem., 2020, 49: 124-135

[109] Campion CL, Li W, Euler WB, et al.. Suppression of toxic compounds produced in the decomposition of lithium-ion battery electrolytes. Electrochem. Solid-State Lett., 2004, 7: A194

[110] Essl C, Golubkov AW, Gasser E, et al.. comprehensive hazard analysis of failing automotive lithium-ion batteries in overtemperature experiments. Batteries, 2020, 6: 30

[111] Mu L, Yang Z, Tao L, et al.. The sensitive surface chemistry of Co-free, Ni-rich layered oxides: identifying experimental conditions that influence characterization results. J. Mater. Chem. A, 2020, 8: 17487-17497

[112] Zhao H, Wang J, Shao H, et al.. Gas generation mechanism in Li-metal batteries. Energy Environ. Mater., 2022, 5: 327-336

[113] Feng XN, Ouyang MG, Liu X, et al.. Thermal runaway mechanism of lithium ion battery for electric vehicles: a review. Energy Stor. Mater., 2018, 10: 246-267

[114] Sun H, Xu GL, Xu YF, et al.. A composite material of uniformly dispersed sulfur on reduced graphene oxide: aqueous one-pot synthesis, characterization and excellent performance as the cathode in rechargeable lithium-sulfur batteries. Nano Res., 2012, 5: 726-738

[115] Wang QS, Sun JH, Yao XL, et al.. Thermal stability of LiPF₆/EC+DEC electrolyte with charged electrodes for lithium ion batteries. Thermochim. Acta, 2005, 437: 12-16

[116] Jo M, Noh M, Oh P, et al.. A new high power LiNi_0.81Co_0.1Al_0.09O₂ cathode material for lithium-ion batteries. Adv. Energy Mater., 2014, 4: 1301583

[117] Wang YD, Jiang JW, Dahn JR. The reactivity of delithiated Li(Ni_1/3Co_1/3Mn_1/3)O₂, Li(Ni_0.8Co_0.15Al_0.05)O₂ or LiCoO₂ with non-aqueous electrolyte. Electrochem. Commun., 2007, 9: 2534-2540

[118] Finegan DP, Scheel M, Robinson JB, et al.. In-operando high-speed tomography of lithium-ion batteries during thermal runaway. Nat. Commun., 2015, 6: 6924

[119] Hu LL, Zhang ZW, Zhou MZ, et al.. Crushing behaviors and failure of packed batteries. Int. J. Impact Eng, 2020, 143: 103618

[120] Juarez-Robles D, Vyas AA, Fear C, et al.. Overcharge and aging analytics of Li-ion cells. J. Electrochem. Soc., 2020, 167: 090547

[121] Markevich E, Salitra G, Aurbach D. Influence of the PVdF binder on the stability of LiCoO₂ electrodes. Electrochem. Commun., 2005, 7: 1298-1304

[122] Kim YS, Lee SH, Son MY, et al.. Succinonitrile as a corrosion inhibitor of copper current collectors for overdischarge protection of lithium ion batteries. ACS Appl. Mater. Interfaces, 2014, 6: 2039-2043

[123] Xu YL, Liu F, Guo JL, et al.. Mechanical properties and thermal runaway study of automotive lithium-ion power batteries. Ionics, 2022, 28: 107-116

[124] Ouyang DX, Weng JW, Chen MY, et al.. Impact of charging and charging rate on thermal runaway behaviors of lithium-ion cells. J. Electrochem. Soc., 2021, 168: 120510

[125] Abd-El-Latif AA, Sichler P, Kasper M, et al.. Insights into thermal runaway of Li-ion cells by accelerating rate calorimetry coupled with external sensors and online gas analysis. Batter. Supercaps, 2021, 4: 1135-1144

[126] Liu YH, Sun PY, Lin SR, et al.. Self-heating ignition of open-circuit cylindrical Li-ion battery pile: towards fire-safe storage and transport. J. Energy Stor., 2020, 32: 101842

[127] Cheng Y, Sun Y, Chu CT, et al.. Stabilizing effects of atomic Ti doping on high-voltage high-nickel layered oxide cathode for lithium-ion rechargeable batteries. Nano Res., 2022, 15: 4091-4099

[128] Yan C, Yang XF, Zhao H, et al.. Controlled Dy-doping to nickel-rich cathode materials in high temperature aerosol synthesis. Proc. Combust. Inst., 2021, 38: 6623-6630

[129] Cho Y, Lee SH, Lee Y, et al.. Spinel-layered core-shell cathode materials for Li-ion batteries. Adv. Energy Mater., 2011, 1: 821-828

[130] Yeh NH, Wang FM, Khotimah C, et al.. Controlling Ni²⁺ from the surface to the bulk by a new cathode electrolyte interphase formation on a Ni-rich layered cathode in high-safe and high-energy-density lithium-ion batteries. ACS Appl. Mater. Interfaces, 2021, 13: 7355-7369

[131] Wang PF, Xia Q, Zhou YC, et al.. Enhancing the overcharged performance of Li(Ni_0.8Co_0.15Al_0.05)O₂ electrodes by CeO₂–Al₂O₃ surface coating. J. Alloys Compd., 2021, 873: 159761

[132] Karki K, Huang Y, Hwang S, et al.. Tuning the activity of oxygen in LiNi_0.8Co_0.15Al_0.05O₂ battery electrodes. ACS Appl. Mater. Inter., 2016, 41(827762-27771

[133] Zhou T, Wang H, Wang Y, et al.. Stabilizing lattice oxygen in slightly Li-enriched nickel oxide cathodes toward high-energy batteries. Chem-US, 2022, 8: 2817-2830

[134] Cho J, Kim H, Park B. Comparison of overcharge behavior of AlPO₄-coated LiCoO₂ and LiNi_0.8Co_0.1Mn_0.1O₂ cathode materials in Li-ion cells. J. Electrochem. Soc., 2004, 151: A1707-A1711

[135] Cho J, Kim TJ, Kim J, et al.. Synthesis, thermal, and electrochemical properties of AlPO4-coated LiNi_0.8Co_0.1Mn_0.1O₂ cathode materials for a Li-ion cell. J. Electrochem. Soc., 2004, 151: A1899-A1904

[136] Jin HZ, Li WJ, Batool N, et al.. A novel safety design strategy to improve the safety performance of LIBs. J. Phys. Chem. C, 2021, 125: 6055-6060

[137] Bi YJ, Liu M, Xiao BW, et al.. Highly stable Ni-rich layered oxide cathode enabled by a thick protective layer with bio-tissue structure. Energy Stor. Mater., 2020, 24: 291-296

[138] Xu GF, Wang LZ, Zhao JL, et al.. Elevated stability of nickel-rich oxide cathode material with concentration gradient of transition metals via a novel size-controllable calcination method. J. Alloys Compd., 2022, 893: 162252

[139] Yang W, Bai CJ, Xiang W, et al.. Dual-modified compact layer and superficial Ti doping for reinforced structural integrity and thermal stability of Ni-rich cathodes. ACS Appl. Mater. Interfaces, 2021, 13: 54997-55006

[140] Zhang N, Stark J, Li HY, et al.. Effects of fluorine doping on nickel-rich positive electrode materials for lithium-ion batteries. J. Electrochem. Soc., 2020, 167: 080515

[141] Sharma L, Yi M, Jo E, et al.. Surface stabilization with fluorine of layered ultrahigh-nickel oxide cathodes for lithiumion batteries. Chem. Mater., 2022, 34: 4514-4522

[142] Lipson AL, Durham JL, LeResche M, et al.. Improving the thermal stability of NMC 622 Li-ion battery cathodes through doping during coprecipitation. ACS Appl. Mater. Interfaces, 2020, 12: 18512-18518

[143] Seenivasan M, Jeyakumar J, Wu YS, et al.. Bifunctional coating layer on Ni-rich cathode materials to enhance electrochemical performance and thermal stability in lithium-ion batteries. Compos. B Eng., 2022, 242: 110083

[144] Reissig F, Ramirez-Rico J, Placke TJ, et al.. The role of protective surface coatings on the thermal stability of delithiated Ni-rich layered oxide cathode materials. Batteries, 2023, 9: 245

[145] Liu YL, Ouyang D, Rathore D, et al.. An evaluation of a systematic series of cobalt-free Ni-rich core-shell materials as positive electrode materials for Li-ion batteries. J. Electrochem. Soc., 2021, 168: 090555

[146] Hong ZW, Dong HC, Han SJ, et al.. Nail penetration-safe LiNi_0.6Co_0.2Mn_0.2O₂ pouch cells enabled by LiMn_0.7Fe_0.3PO₄ cathode safety additive. J. Power Sources, 2021, 512: 230505

[147] Lim DA, Shin YK, Seok JH, et al.. Cathode electrolyte interphase-forming additive for improving cycling performance and thermal stability of Ni-rich LiNi_xCo_yMn_1−x−yO₂ cathode materials. ACS Appl. Mater. Interfaces, 2022, 14: 54688-54697

[148] Zhang C, Li T, Xue B, et al.. Synergistic modification of Ni-rich full concentration gradient materials with enhanced thermal stability. Chem. Eng. J., 2023, 451: 138518

[149] Wang B, Zhao HL, Cai FP, et al.. Surface engineering with ammonium niobium oxalate: a multifunctional strategy to enhance electrochemical performance and thermal stability of Ni-rich cathode materials at 4.5 V cutoff potential. Electrochim. Acta, 2022, 403: 139636

[150] Ni LS, Zhang S, Di AD, et al.. Challenges and strategies towards single-crystalline Ni-rich layered cathodes. Adv. Energy Mater., 2022, 12: 2201510

[151] Chiba K, Yoshizawa A, Isogai Y. Thermal safety diagram for lithium-ion battery using single-crystal and polycrystalline particles LiNi_0.8Co_0.1Mn_0.1O₂. J. Energy Stor., 2020, 32: 101775

[152] Zhao HC, Bai Y, Jin HF, et al.. Unveiling thermal decomposition kinetics of single-crystalline Ni-Rich LiNi_0.88Co_0.07Mn_0.05O₂ cathode for safe lithium-ion batteries. Chem. Eng. J., 2022, 435: 134927

[153] Fan XM, Hu GR, Zhang B, et al.. Crack-free single-crystalline Ni-rich layered NCM cathode enable superior cycling performance of lithium-ion batteries. Nano Energy, 2020, 70: 104450

[154] Kong XB, Zhang YG, Li JY, et al.. Single-crystal structure helps enhance the thermal performance of Ni-rich layered cathode materials for lithium-ion batteries. Chem. Eng. J., 2022, 434: 134638

[155] Huang H, Zhang LP, Tian HY, et al.. Pulse high temperature sintering to prepare single-crystal high nickel oxide cathodes with enhanced electrochemical performance. Adv. Energy Mater., 2023, 13: 2203188

[156] Zhou WD, Huang H, Liu XH, et al.. Perspective on the preparation methods of single crystalline high nickel oxide cathode materials. Adv. Energy Mater., 2023, 13: 2300378

[157] Noguchi T, Hasegawa T, Yamauchi H, et al.. Effect of using fluorinated ether and sulfone as electrolyte solvents for lithium ion batteries with lithium-rich layered cathodes and silicon oxide anodes. ECS Trans., 2017, 80: 291-303

[158] Yun JJ, Zhang L, Qu QT, et al.. A binary cyclic carbonates- based electrolyte containing propylene carbonate and trifluoropropylene carbonate for 5V lithium-ion batteries. Electrochim. Acta, 2015, 167: 151-159

[159] Arai J. No-flash-point electrolytes applied to amorphous carbon/Li_1+xMn₂O₄ cells for EV use. J. Power Sources, 2003, 119(120/121388-392

[160] Naoi K, Iwama E, Ogihara N, et al.. Nonflammable hydrofluoroether for lithium-ion batteries: enhanced rate capability, cyclability, and low-temperature performance. J. Electrochem. Soc., 2009, 156: A272

[161] Naoi K, Iwama E, Honda Y, et al.. Discharge behavior and rate performances of lithium-ion batteries in nonflammable hydrofluoroethers(II). J. Electrochem. Soc., 2010, 157: A190

[162] Cormier MME, Zhang N, Liu A, et al.. Impact of dopants (Al, Mg, Mn, Co) on the reactivity of Li_xNiO₂ with the electrolyte of Li-ion batteries. J. Electrochem. Soc., 2019, 166: A2826-A2833

[163] Buhrmester C, Moshurchak LM, Wang RL, et al.. The use of 2,2,6,6-tetramethylpiperinyl-oxides and derivatives for redox shuttle additives in Li-ion cells. J. Electrochem. Soc., 2006, 153: A1800

[164] Weng W, Zhang ZC, Schlueter JA, et al.. Improved synthesis of a highly fluorinated boronic ester as dual functional additive for lithium-ion batteries. J. Power Sources, 2011, 196: 2171-2178

[165] Zhang L, Zhang ZC, Redfern PC, et al.. Molecular engineering towards safer lithium-ion batteries: a highly stable and compatible redox shuttle for overcharge protection. Energy Environ. Sci., 2012, 5: 8204-8207

[166] Buhrmester C, Chen J, Moshurchak L, et al.. Studies of aromatic redox shuttle additives for LiFePO₄-based Li-ion cells. J. Electrochem. Soc., 2005, 152: A2390

[167] Chen J, Buhrmester C, Dahn JR. Chemical overcharge and overdischarge protection for lithium-ion batteries. Electrochem. Solid-State Lett., 2005, 8: A59

[168] Dahn JR, Jiang JW, Moshurchak LM, et al.. High-rate overcharge protection of LiFePO₄-based Li-ion cells using the redox shuttle additive 2,5-ditertbutyl-1,4-dimethoxybenzene. J. Electrochem. Soc., 2005, 152: A1283

[169] Wang ZY, Jiang LH, Liang C, et al.. Effects of 3-fluoroanisol as an electrolyte additive on enhancing the overcharge endurance and thermal stability of lithium-ion batteries. J. Electrochem. Soc., 2020, 167: 130517

[170] Vogl U, Schmitz A, Stock C, et al.. Investigation of N-ethyl-2-pyrrolidone (NEP) as electrolyte additive in regard to overcharge protecting characteristics. J. Electrochem. Soc., 2014, 161: A1407-A1414

[171] Dippel C, Schmitz R, Müller R, et al.. Carbene adduct as overcharge protecting agent in lithium ion batteries. J. Electrochem. Soc., 2012, 159: A1587-A1590

[172] Ji WX, Huang H, Huang XK, et al.. A redox-active organic cation for safer high energy density Li-ion batteries. J. Mater. Chem. A, 2020, 8: 17156-17162

[173] Huang JH, Shkrob IA, Wang PQ, et al.. 1,4-Bis(trimethylsilyl)-2,5-dimethoxybenzene: a novel redox shuttle additive for overcharge protection in lithium-ion batteries that doubles as a mechanistic chemical probe. J. Mater. Chem. A, 2015, 3: 7332-7337

[174] Wang RL, Moshurchak LM, Lamanna WM, et al.. A combined computational/experimental study on tertbutyl- and methoxy-substituted benzene derivatives as redox shuttles for lithium-ion cells. J. Electrochem. Soc., 2008, 155: A66

[175] Zhang ZA, Peng B, Lu H, et al.. Application of anisole, 2-bromoanisole and 3-bromoanisole as overcharge protection additives in lithium-ion batteries. Acta Chim. Sinica, 2013, 71: 798

[176] Moshurchak LM, Buhrmester C, Wang RL, et al.. Comparative studies of three redox shuttle molecule classes for overcharge protection of LiFePO₄-based Li-ion cells. Electrochim. Acta, 2007, 52: 3779-3784

[177] Dalavi S, Xu MQ, Ravdel B, et al.. Nonflammable electrolytes for lithium-ion batteries containing dimethyl methylphosphonate. J. Electrochem. Soc., 2010, 157: A1113

[178] Jin Z, Wu L, Song Z, et al.. A new class of phosphates as co-solvents for nonflammable lithium ion batteries electrolytes. ECS Electrochem. Lett., 2012, 1: A55-A58

[179] Sazhin SV, Harrup MK, Gering KL. Characterization of low-flammability electrolytes for lithium-ion batteries. J. Power Sources, 2011, 196: 3433-3438

[180] Isken P, Dippel C, Schmitz R, et al.. High flash point electrolyte for use in lithium-ion batteries. Electrochim. Acta, 2011, 56: 7530-7535

[181] Fang SH, Wang GJ, Qu L, et al.. A novel mixture of diethylene glycol diethylether and non-flammable methyl-nonafluorobutyl ether as a safe electrolyte for lithium ion batteries. J. Mater. Chem. A, 2015, 3: 21159-21166

[182] Pham HQ, Lee HY, Hwang EH, et al.. Non-flammable organic liquid electrolyte for high-safety and high-energy density Li-ion batteries. J. Power Sources, 2018, 404: 13-19

[183] Wang JH, Yamada Y, Sodeyama K, et al.. Fire-extinguishing organic electrolytes for safe batteries. Nat. Energy, 2018, 3: 22-29

[184] Chen SR, Zheng JM, Yu L, et al.. High-efficiency lithium metal batteries with fire-retardant electrolytes. Joule, 2018, 2: 1548-1558

[185] Haynes WM. CRC Handbook of Chemistry and Physics, 201797Taylor & Francis Group, CRC Press

[186] Xia X, Ping P, Dahn JR. The reactivity of charged electrode materials with electrolytes containing the flame retardant, triphenyl phosphate. J. Electrochem. Soc., 2012, 159: A1834-A1837

[187] Doughty DH, Roth EP, Crafts CC, et al.. Effects of additives on thermal stability of Li ion cells. J. Power Sources, 2005, 146: 116-120

[188] Ding MS, Xu K, Jow TR. Effects of tris(2,2,2-trifluoroethyl) phosphate as a flame-retarding cosolvent on physicochemical properties of electrolytes of LiPF₆ in EC-PC-EMC of 3:3:4 weight ratios. J. Electrochem. Soc., 2002, 149: A1489

[189] Wu L, Song ZP, Liu LS, et al.. A new phosphate-based nonflammable electrolyte solvent for Li-ion batteries. J. Power Sources, 2009, 188: 570-573

[190] Xiang HF, Xu HY, Wang ZZ, et al.. Dimethyl methylphosphonate (DMMP) as an efficient flame retardant additive for the lithium-ion battery electrolytes. J. Power Sources, 2007, 173: 562-564

[191] Zeng ZQ, Wu BB, Xiao LF, et al.. Safer lithium ion batteries based on nonflammable electrolyte. J. Power Sources, 2015, 279: 6-12

[192] Izquierdo-Gonzales S, Li WT, Lucht BL. Hexamethylphosphoramide as a flame retarding additive for lithium-ion battery electrolytes. J. Power Sources, 2004, 135: 291-296

[193] Ge SH, Leng YJ, Liu T, et al.. A new approach to both high safety and high performance of lithium-ion batteries. Sci. Adv., 2020, 6: eaay7633

[194] Yan P, Zhu Y, Pan X, et al.. A novel flame-retardant electrolyte additive for safer lithium-ion batteries. Int. J. Energ. Res., 2021, 45: 2776-2784

[195] Huang PH, Chang SJ, Li CC. Encapsulation of flame retardants for application in lithium-ion batteries. J. Power Sources, 2017, 338: 82-90

[196] Xia L, Xia YG, Liu ZP. A novel fluorocyclophosphazene as bifunctional additive for safer lithium-ion batteries. J. Power Sources, 2015, 278: 190-196

[197] Zheng QF, Yamada Y, Shang R, et al.. A cyclic phosphate- based battery electrolyte for high voltage and safe operation. Nat. Energy, 2020, 5: 291-298

[198] Guo F, Ozaki Y, Nishimura K, et al.. Influence of lithium salts on the combustion characteristics of dimethyl carbonate-based electrolytes using a wick combustion method. Combust. Flame, 2020, 213: 314-321

[199] Shaffer AR, Deligonul N, Scherson DA, et al.. A hybrid lithium oxalate−phosphinate salt. Inorg. Chem., 2010, 23(49): 10756-10758

[200] Rectenwald MF, Gaffen JR, Rheingold AL, et al.. Phosphoryl- rich flame-retardant ions (FRIONs): towards safer lithium- ion batteries. Ange. Chem. Int. Ed., 2014, 53: 4173-4176

[201] Xu K, Ding MS, Zhang SS, et al.. Evaluation of fluorinated alkyl phosphates as flame retardants in electrolytes for Li-ion batteries. I. Physical and electrochemical properties. J. Electrochem. Soc., 2003, 150: A161

[202] Zhang HP, Xia Q, Wang B, et al.. Vinyl-tris-(methoxydiethoxy)silane as an effective and ecofriendly flame retardant for electrolytes in lithium ion batteries. Electrochem. Commun., 2009, 11: 526-529

[203] Dai WH, Dong N, Xia YG, et al.. Localized concentrated high-concentration electrolyte enhanced stability and safety for high voltage Li-ion batteries. Electrochim. Acta, 2019, 320: 134633

[204] von Aspern N, Röser S, Rezaei Rad B, et al.. Phosphorus additives for improving high voltage stability and safety of lithium ion batteries. J. Fluor. Chem., 2017, 198: 24-33

[205] Jiang LH, Wang QS, Li K, et al.. A self-cooling and flameretardant electrolyte for safer lithium ion batteries. Sustain. Energy Fuels, 2018, 2: 1323-1331

[206] Feng JK, Ai XP, Cao YL, et al.. Possible use of non-flammable phosphonate ethers as pure electrolyte solvent for lithium batteries. J. Power Sources, 2008, 177: 194-198

[207] Hu CY, Li XH. Non-flammable electrolytes based on trimethyl phosphate solvent for lithium-ion batteries. T. Nonferr. Metal Soc., 2005, 15: 1380-1387

[208] Xu K, Ding MS, Zhang SS, et al.. An attempt to formulate nonflammable lithium ion electrolytes with alkyl phosphates and phosphazenes. J. Electrochem. Soc., 2002, 149: A622

[209] Baginska M, Sottos NR, White SR. Core-shell microcapsules containing flame retardant tris(2-chloroethyl phosphate) for lithium-ion battery applications. ACS Omega, 2018, 3: 1609-1613

[210] Murmann P, Mönnighoff X, von Aspern N, et al.. Influence of the fluorination degree of organophosphates on flammability and electrochemical performance in lithium ion batteries: studies on fluorinated compounds deriving from triethyl phosphate. J. Electrochem. Soc., 2016, 163: A751-A757

[211] Doi T, Shimizu Y, Hashinokuchi M, et al.. Dilution of highly concentrated LiBF4/propylene carbonate electrolyte solution with fluoroalkyl ethers for 5-V LiNi_0.5Mn_1.5O₄ positive electrodes. J. Electrochem. Soc., 2017, 164: A6412-A6416

[212] Moon H, Mandai T, Tatara R, et al.. Solvent activity in electrolyte solutions controls electrochemical reactions in Li-ion and Li-sulfur batteries. J. Phys. Chem. C, 2015, 119: 3957-3970

[213] Wang H, Matsui M, Kuwata H, et al.. A reversible dendritefree high-areal-capacity lithium metal electrode. Nat. Commun., 2017, 8: 1-9

[214] Watanabe M, Dokko K, Ueno K, et al.. From ionic liquids to solvate ionic liquids: challenges and opportunities for next generation battery electrolytes. B. Chem. Soc. Jpn., 2018, 91: 1660-1682

[215] Kim HT, Kang J, Mun J, et al.. Pyrrolinium-based ionic liquid as a flame retardant for binary electrolytes of lithium ion batteries. ACS Sustain. Chem. Eng., 2016, 4: 497-505

[216] Wu FL, Schür AR, Kim GT, et al.. A novel phosphonium ionic liquid electrolyte enabling high-voltage and high-energy positive electrode materials in lithium-metal batteries. Energy Stor. Mater., 2021, 42: 826-835

[217] Montanino M, Moreno M, Carewska M, et al.. Mixed organic compound-ionic liquid electrolytes for lithium battery electrolyte systems. J. Power Sources, 2014, 269: 608-615

[218] Wilken S, Xiong SZ, Scheers J, et al.. Ionic liquids in lithium battery electrolytes: composition versus safety and physical properties. J. Power Sources, 2015, 275: 935-942

[219] Yan SX, Wang YL, Chen TH, et al.. Regulated interfacial stability by coordinating ionic liquids with fluorinated solvent for high voltage and safety batteries. J. Power Sources, 2021, 491: 229603

[220] Zeng ZQ, Murugesan V, Han KS, et al.. Non-flammable electrolytes with high salt-to-solvent ratios for Li-ion and Limetal batteries. Nat. Energy, 2018, 3: 674-681

[221] Chen XB, Chen SL, Lin YS, et al.. Multi-functional ceramic-coated separator for lithium-ion batteries safety tolerance improvement. Ceram. Int., 2020, 46: 24689-24697

[222] Zhang DX, Ding L, Wu T, et al.. Facile preparation of a lithium-ion battery separator with thermal shutdown function based on polypropylene/polyethylene microsphere composites. Ind. Eng. Chem. Res., 2021, 60: 18530-18539

[223] Ji WX, Jiang BL, Ai FX, et al.. Temperature-responsive microspheres-coated separator for thermal shutdown protection of lithium ion batteries. RSC Adv., 2015, 5: 172-176

[224] Chen Z, Hsu P, Lopez J, et al.. Fast and reversible thermoresponsive polymer switching materials for safer batteries. Nat. Energy, 2016, 1: 15009

[225] Li D, Shi DQ, Yuan ZZ, et al.. A low cost shutdown sandwich- like composite membrane with superior thermo-stability for lithium-ion battery. J. Membr. Sci., 2017, 542: 1-7

[226] Liu J, Liu YB, Yang WX, et al.. Lithium ion battery separator with high performance and high safety enabled by tri-layered SiO₂@PI/m-PE/SiO₂@PI nanofiber composite membrane. J. Power Sources, 2018, 396: 265-275

[227] Nho YC, Sohn JY, Shin J, et al.. Preparation of nanocomposite γ-Al₂O₃/polyethylene separator crosslinked by electron beam irradiation for lithium secondary battery. Radiat. Phys. Chem., 2017, 132: 65-70

[228] Zhang XK, Li N, Hu ZM, et al.. Poly(p-phenylene terephthalamide) modified PE separators for lithium ion batteries. J. Membr. Sci., 2019, 581: 355-361

[229] Wei ZZ, Gu JY, Zhang FR, et al.. Core-shell structured nanofibers for lithium ion battery separator with wide shutdown temperature window and stable electrochemical performance. ACS Appl. Polym. Mater., 2020, 2: 1989-1996

[230] Orendorff CJ, Lambert TN, Chavez CA, et al.. Polyester separators for lithium-ion cells: improving thermal stability and abuse tolerance. Adv. Energy Mater., 2013, 3: 314-320

[231] Dai DM, Yang LF, Zheng SM, et al.. Modified alginate dressing with high thermal stability as a new separator for Li-ion batteries. Chem. Commun., 2020, 56: 6149-6152

[232] Li H, Lin F, Wang H, et al.. Enhanced thermal stability and wettability of an electrospun fluorinated poly(aryl ether ketone) fibrous separator for lithium-ion batteries. New J. Chem., 2020, 44: 3838-3846

[233] Huang ZH, Chen JM, Huo YP, et al.. Heat resistant microporous membranes based on soluble poly(aryl ether ketone) copolymers for lithium ion battery separator. J. Appl. Polym. Sci., 2021, 138: 50895

[234] Cho SJ, Choi H, Youk JH. Evaluation of PBI nanofiber membranes as a high-temperature resistance separator for lithium-ion batteries. Fiber. Polym., 2020, 5(21993-998

[235] Lin G, Cao T, Bai ZX, et al.. Poly(arylene ether nitrile) porous membranes with adjustable pore size for high temperature resistance and high-performance lithium-ion batteries. Microporous Mesoporous Mater., 2021, 324: 111276

[236] Pan JL, Zhang Z, Zhou ML, et al.. Aramid nanofiber reinforced cellulose paper for high-safety lithium-ion batteries. Cellulose, 2021, 28: 10579-10588

[237] Habumugisha JC, Usha ZR, Yu R, et al.. Thermally stable and high electrochemical performance ultra-high molecular weight polyethylene/poly(4-methyl-1-pentene) blend film used as Li-ion battery separator. Appl. Mater. Today, 2021, 24: 101136

[238] Xie Y, Chen X, Han K, et al.. Natural halloysite nanotubes-coated polypropylene membrane as dual-function separator for highly safe Li-ion batteries with improved cycling and thermal stability. Electrochim. Acta, 2021, 379: 138182

[239] Chen DX, Wang X, Liang JY, et al.. A novel electrospinning polyacrylonitrile separator with dip-coating of zeolite and phenoxy resin for Li-ion batteries. Membranes, 2021, 11: 267

[240] Liu AM, Li SY, Jiang ZY, et al.. A renewable membrane with high ionic conductivity and thermal stability for Li-ion batteries. J. Power Sources, 2022, 521: 230947

[241] Fenton DE, Parker JM, Wright PV. Complexes of alkali metal ions with poly(ethylene oxide). Polymer, 1973, 14: 589-589

[242] Armand MB. Polymer electrolytes. Annual Review. Mater. Sci., 1986, 16: 245-261

[243] Wang C, Yang T, Zhang W, et al.. Hydrogen bonding enhanced SiO₂/PEO composite electrolytes for solid-state lithium batteries. J. Mater. Chem. A, 2022, 10: 3400-3408

[244] Tang W, Tang S, Zhang C, et al.. Simultaneously enhancing the thermal stability, mechanical modulus, and electrochemical performance of solid polymer electrolytes by Incorporating 2D sheets. Adv. Energy Mater., 2018, 8: 1800866

[245] Zhang Z, Huang Y, Gao H, et al.. 3D glass fiber cloth reinforced polymer electrolyte for solid-state lithium metal batteries. J. Membr. Sci., 2021, 621: 118940

[246] Gao L, Liang H, Li J, et al.. The high-strength and ultra-thin composite electrolyte using one-step electrospinning/electrostatic spraying process for interface control in all-solid-state lithium metal battery. J. Power Sources, 2021, 515: 230622

[247] Zhou D, Shanmukaraj D, Tkacheva A, et al.. Polymer electrolytes for lithium-based batteries: advances and prospects. Chem, 2019, 5: 2326-2352

[248] BYD: BYD’s new blade battery set to redefine EV safety standards. BYD Motors Inc. https://en.byd.com/news/byds-new-blade-battery-set-to-redefine-ev-safety-standards/ (2023). Accessed 21 Sept 2023

[249] Morita M, Niida Y, Yoshimoto N, et al.. Polymeric gel electrolyte containing alkyl phosphate for lithium-ion batteries. J. Power Sources, 2005, 146: 427-430

[250] Lalia BS, Fujita T, Yoshimoto N, et al.. Electrochemical performance of nonflammable plymeric gel electrolyte containing triethylphosphate. J. Power Sources, 2009, 186: 211-215

[251] Luo CZ, Shen T, Ji HQ, et al.. Mechanically robust gel polymer electrolyte for an ultrastable sodium metal battery. Small, 2020, 16: 1906208

[252] Zhang JQ, Sun B, Huang XD, et al.. Honeycomb-like porous gel polymer electrolyte membrane for lithium ion batteries with enhanced safety. Sci. Rep., 2014, 4: 1-7

[253] Xu D, Su JM, Jin J, et al.. In situ generated fireproof gel polymer electrolyte with Li_6.4Ga_0.2La₃Zr₂O₁₂ as initiator and ionconductive filler. Adv. Energy Mater., 2019, 9: 1900611

[254] Hu ZY, Chen JJ, Guo Y, et al.. Fire-resistant, high-performance gel polymer electrolytes derived from poly(ionic liquid)/ P(VDF-HFP) composite membranes for lithium ion batteries. J. Membr. Sci., 2020, 599: 117827

Funding

National Natural Science Foundation of China(22279066)

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