Effects of gradient concentration on the microstructure and electrochemical performance of LiNi_0.6Co_0.2Mn_0.2O₂ cathode materials

Abstract

Nickel(Ni)-rich layered materials have attracted considerable interests as promising cathode materials for lithium ion batteries (LIBs) owing to their higher capacities and lower cost. Nevertheless, Mn-rich cathode materials usually suffer from poor cyclability caused by the unavoidable side-reactions between Ni⁴⁺ ions on the surface and electrolytes. The design of gradient concentration (GC) particles with Ni-rich inside and Mn-rich outside is proved to be an efficient way to address the issue. Herein, a series of LiNi_0.6Co_0.2Mn_0.2O₂ (LNCM622) materials with different GCs (the atomic ratio of Ni/Mn decreasing from the core to the outer layer) have been successfully synthesized via rationally designed co-precipitation process. Experimental results demonstrate that the GC of LNCM622 materials plays an important role in their microstructure and electrochemical properties. The as-prepared GC3.5 cathode material with optimal GC can provide a shorter pathway for lithium-ion diffusion and stabilize the near-surface region, and finally achieve excellent electrochemical performances, delivering a discharge capacity over 176 mAh·g⁻¹ at 0.2 C rate and exhibiting capacity retention up to 94% after 100 cycles at 1 C. The rationally-designed co-precipitation process for fabricating the Ni-rich layered cathode materials with gradient composition lays a solid foundation for the preparation of high-performance cathode materials for LIBs.

Graphical abstract

Keywords

gradient concentration / Ni-rich / LiNi_0.6Co_0.2-Mn_0.2O₂ / electrochemical performance / lithium-ion battery

References

[1] Tang Y, Zhang Y, Li W, Ma B, Chen X. Rational material design for ultrafast rechargeable lithium-ion batteries. Chemical Society Reviews, 2015, 44(17): 5926–5940

[2] Shi J L, Xiao D D, Ge M, Yu X, Chu Y, Huang X, Zhang X D, Yin Y X, Yang X Q, Guo Y G, High-capacity cathode material with high voltage for Li-ion batteries. Advanced Materials, 2018, 30(9): 1705575–1705583

[3] Xu J, Lin F, Doeff M M, Tong W. A review of Ni-based layered oxides for rechargeable Li-ion batteries. Journal of Materials Chemistry. A, Materials for Energy and Sustainability, 2017, 5(3): 874–901

[4] Lin F, Nordlund D, Markus I M, Weng T C, Xin H L, Doeff M M. Profiling the nanoscale gradient in stoichiometric layered cathode particles for lithium-ion batteries. Energy & Environmental Science, 2014, 7(9): 3077–3085

[5] Kim J, Cho H, Jeong H Y, Ma H, Lee J, Hwang J, Park M, Cho J. Self-Induced concentration gradient in nickel-rich cathodes by sacrificial polymeric bead clusters for high-energy lithium-ion batteries. Advanced Energy Materials, 2017, 7(12): 1602559

[6] Liang L, Du K, Peng Z, Cao Y, Duan J, Jiang J, Hu G. Co–precipitation synthesis of N_i0.6Co_0.2Mn_0.2(OH)₂ precursor and characterization of LiNi_0.6Co_0.2Mn_0.2O₂ cathode material for secondary lithium batteries. Electrochimica Acta, 2014, 130: 82–89

[7] Ren D, Shen Y, Yang Y, Shen L, Levin B D A, Yu Y, Muller D A, Abruna H D. Systematic optimization of battery materials: Key parameter optimization for the scalable synthesis of uniform, high-energy, and high stability LiNi_0.6Mn_0.2Co_0.2O₂ cathode material for lithium-ion batteries. ACS Applied Materials & Interfaces, 2017, 9(41): 35811–35819

[8] Liu S, Zhang C, Su Q, Li L, Su J, Huang T, Chen Y, Yu A. Enhancing electrochemical performance of LiNi_0.6Co_0.2Mn_0.2O₂ by lithium-ion conductor surface modification. Electrochimica Acta, 2017, 224: 171–177

[9] Zhang T, Paillard E. Recent advances toward high voltage, EC-free electrolytes for graphite-based Li-ion battery. Frontiers of Chemical Science and Engineering, 2018, 12(3): 577–591

[10] Ding R Q, Liu H, Wang L, Liang G C. Effect of spray drying technological conditions on the performance of LiFePO₄/C cathode materials with high energy density. Ionics, 2019, 25(12): 5633–5642

[11] Ma Y, Wang L, Zuo X, Nan J. Co-precipitation spray-drying synthesis and electrochemical performance of stabilized LiNi_0.5Mn_1.5O₄ cathode materials. Journal of Solid State Electrochemistry, 2018, 22(7): 1963–1969

[12] Zhang M J, Hu X B, Li M F, Duan Y D, Yang L Y, Yin C, Ge M Y, Xiao X H, Lee W K, Amine K, Cooling induced surface reconstruction during synthesis of high-Ni hayered oxides. Advanced Energy Materials, 2019, 9(43): 1901915

[13] Du H, Zhang X, Chen Z, Wu D, Zhang Z, Li J. Carbon coating and Al-doping to improve the electrochemistry of Li₂CoSiO₄ polymorphs as cathode materials for lithium-ion batteries. RSC Advances, 2018, 8(40): 22813–22822

[14] Hou P, Zhang H, Zi Z, Zhang L, Xu X. Core–shell and concentration-gradient cathodes prepared via co-precipitation reaction for advanced lithium-ion batteries. Journal of Materials Chemistry. A, Materials for Energy and Sustainability, 2017, 5(9): 4254–4279

[15] Zhao Y, Liu J, Wang S, Ji R, Xia Q, Ding Z, Wei W, Liu Y, Wang P, Ivey D G. Surface structural transition induced by gradient polyanion-doping in Li-rich layered oxides: Implications for enhanced electrochemical performance. Advanced Functional Materials, 2016, 26(26): 4760–4767

[16] Kim U H, Ryu H H, Kim J H, Mücke R, Kaghazchi P, Yoon C S, Sun Y K. Microstructure-controlled Ni-rich cathode material by microscale compositional partition for next-generation electric vehicles. Advanced Energy Materials, 2019, 9(15): 1803902

[17] Kong D F, Hu J T, Chen Z F, Song K P, Li C, Weng M Y, Li M F, Wang R, Liu T C, Liu J J, Ti-gradient doping to stabilize layered surface structure for high performance high-Ni oxide cathode of Li-ion battery. Advanced Energy Materials, 2019, 9(14): 1901756

[18] Pham H Q, Kim G, Jung H M, Song S W. Fluorinated polyimide as a novel high-voltage binder for high-capacity cathode of lithium-ion batteries. Advanced Functional Materials, 2018, 28(2): 1704690

[19] Zhang J, Yang Z, Gao R, Gu L, Hu Z, Liu X. Suppressing the structure deterioration of Ni-rich LiNi_0.8Co_0.1Mn_0.1O₂ through atom-scale interfacial integration of self-forming hierarchical spinel layer with Ni gradient concentration. ACS Applied Materials & Interfaces, 2017, 9(35): 29794–29803

[20] Zhang Y, Wang Z B, Nie M, Yu F D, Xia Y F, Liu B S, Xue Y, Zheng L L, Wu J. A simple method for industrialization to enhance the tap density of LiNi_0.5Co_0.2Mn_0.3O₂ cathode material for high-specific volumetric energy lithium-ion batteries. RSC Advances, 2016, 6(70): 65941–65949

[21] Liao J Y, Oh S M, Manthiram A. Core/double-shell type gradient Ni-rich LiNi_0.76Co_0.10Mn_0.14O₂ with high capacity and long cycle life for lithium-ion batteries. ACS Applied Materials & Interfaces, 2016, 8(37): 24543–24549

[22] Li Y, Xu R, Ren Y, Lu J, Wu H, Wang L, Miller D J, Sun Y K, Amine K, Chen Z. Synthesis of full concentration gradient cathode studied by high energy X-ray diffraction. Nano Energy, 2016, 19: 522–531

Acknowledgements

The authors are grateful to the financial support of the National Natural Science Foundation of China (Grant Nos. 91834301, 91534102 and 21271058). This work is also supported by Science and Technology Project of Anhui Province (Nos. 201903a05020021 and 17030901067).ƒ

Electronic Supplementary Material

Supplementary material is available in the online version of this article at https://doi.org/10.1007/s11705-020-1918-9 and is accessible for authorized users.

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