Highly crystalline covalent triazine frameworks modified separator for lithium metal batteries

Abstract

Covalent organic frameworks (COFs) that selectively enable lithium ions transport by their abundant sub-nano or nanosized pores and polar skeleton are considered as emerging coating materials for separators of lithium metal batteries. However, the COF-coated separators that combine high ionic conductivity with excellent lithium ions transference number ($ {t_{L i^{+}} } $) are still challenging, as the coating layer may increase the transport resistance of ions through the separator due to the elongated pathway. Different from conventional strategies that always focus on developing COFs with distinct structural motifs, this work proposes a crystallinity engineering tactic to improve the ion transport behaviors and thus battery performance. Amorphous (AM-CTF) and highly crystalline covalent triazine frameworks (HC-CTF) were successfully synthesized, and the effect of crystallinity of CTFs on the electrochemical properties of the separators and the battery performance are fully studied. Compared to amorphous covalent triazine framework, HC-CTF features a more regular structure and higher surface area, which further improves the $ {t_{L i^{+}} } $ (0.60) and ionic conductivity (0.67 mS cm^-1) of the coated separators. The LiFePO₄/Li cells assembled with the HC-CTF-coated separator exhibit an ultralong lifespan and extremely high-capacity retention (45.4% at 1 C for 1,000 cycles). This work opens up a new strategy for designing high-performance separators of lithium batteries.

Keywords

Covalent triazine frameworks / COF-modified separator / crystallinity of COF / lithium metal batteries

References

[1] Li D,Chen B.Advanced current collector materials for high-performance lithium metal anodes.Small2022;18:e2200010

[2] Zhang X,Xu R.Columnar lithium metal anodes.Angew Chem2017;129:14395-9

[3] Cheng XB,Zhao CZ,Zhang JG.A review of solid electrolyte interphases on lithium metal anode.Adv Sci2016;3:1500213

[4] Zhang K,Park M,Kang Y.Recent developments of the lithium metal anode for rechargeable non-aqueous batteries.Adv Energy Mater2016;6:1600811

[5] Wang Q,Shen Y.Confronting the challenges in lithium anodes for lithium metal batteries.Adv Sci2021;8:e2101111 PMCID:PMC8425877

[6] Liu K,Shi L,Yuan S.Ionic liquids for high performance lithium metal batteries.J Energy Chem2021;59:320-33

[7] Li G.Regulating mass transport behavior for high-performance lithium metal batteries and fast-charging lithium-ion batteries.Adv Energy Mater2021;11:2002891

[8] Shen X,Cheng X,Huang J.Beyond lithium ion batteries: Higher energy density battery systems based on lithium metal anodes.Energy Stor Mater2018;12:161-75

[9] Li G,Huang Q.Stable metal battery anodes enabled by polyethylenimine sponge hosts by way of electrokinetic effects.Nat Energy2018;3:1076-83

[10] Chen Y,Wang K.Lithium dendrites inhibition via diffusion enhancement.Adv Energy Mater2019;9:1900019

[11] Albertus P,Litzelman S.Status and challenges in enabling the lithium metal electrode for high-energy and low-cost rechargeable batteries.Nat Energy2018;3:16-21

[12] Zhou P,Xiang Y.Strategies to enhance Li⁺ transference number in liquid electrolytes for better lithium batteries.Nano Res2023;16:8055-71

[13] Liang J,Liao X.A nano-shield design for separators to resist dendrite formation in lithium-metal batteries.Angew Chem2020;132:6623-8

[14] Wang G,Xie D.Suppressing dendrite growth by a functional electrolyte additive for robust Li metal anodes.Energy Stor Mater2019;23:701-6

[15] Din MMU.Metal coated polypropylene separator with enhanced surface wettability for high capacity lithium metal batteries.Sci Rep2019;9:16795 PMCID:PMC6856152

[16] Wang C,Jin Y,Wang H.Functional separator enabled by covalent organic frameworks for high-performance Li metal batteries.Small2023;19:e2300023

[17] Chen H,Xu Q,Shao Z.Plasma activation and atomic layer deposition of TiO₂ on polypropylene membranes for improved performances of lithium-ion batteries.J Membrane Sci2014;458:217-24

[18] Wu J,Li X.Ultralight layer-by-layer self-assembled MoS₂-polymer modified separator for simultaneously trapping polysulfides and suppressing lithium dendrites.Adv Energy Mater2018;8:1802430

[19] Naren T,Qing P.Stabilizing lithium metal batteries by synergistic effect of high ionic transfer separator and lithium-boron composite material anode.ACS Nano2023;17:20315-24

[20] Zhang Y,Wang Z.Functional polyethylene separator with impurity entrapment and faster Li⁺ ions transfer for superior lithium-ion batteries.J Colloid Interface Sci2022;607:742-51

[21] Jin R,Zhou H.High Li⁺ ionic flux separator enhancing cycling stability of lithium metal anode.ACS Sustain Chem Eng2018;6:2961-8

[22] Ding SY.Covalent organic frameworks (COFs): from design to applications.Chem Soc Rev2013;42:548-68

[23] An Y,Liu Y.Designs and applications of multi-functional covalent organic frameworks in rechargeable batteries.Energy Stor Mater2021;41:354-79

[24] Zhou L,Park M.Structural engineering of covalent organic frameworks for rechargeable batteries.Adv Energy Mater2021;11:2003054

[25] Ye H,Li Y.Advanced covalent-organic framework materials for sodium-ion battery.Prog Nat Sci2023;33:754-66

[26] Sun T,Guo W,Zhang Q.Covalent-organic frameworks: advanced organic electrode materials for rechargeable batteries.Adv Energy Mater2020;10:1904199

[27] Chang H,Han X.Recent developments in advanced anode materials for lithium-ion batteries.Energy Mater2022;1:100003

[28] Gao Z,Zhao G,Guo H.Covalent organic frameworks for solid-state electrolytes of lithium metal batteries.J Mater Chem A2022;10:7497-516

[29] Niu C,Dai C,Xu Y.High-voltage-tolerant covalent organic framework electrolyte with holistically oriented channels for solid-state lithium metal batteries with nickel-rich cathodes.Angew Chem Int Ed2021;60:24915-23

[30] Cao Y,Wang H,Pan F.Covalent organic framework for rechargeable batteries: mechanisms and properties of ionic conduction.Adv Energy Mater2022;12:2200057

[31] Cao Y,Li G.Ion selective covalent organic framework enabling enhanced electrochemical performance of lithium-sulfur batteries.Nano Lett2021;21:2997-3006

[32] Shi J,Xiong B,Lu Q.Molecular design and post-synthetic vulcanization on two-dimensional covalent organic framework@rGO hybrids towards high-performance sodium-ion battery cathode.Chem Eng J2023;453:139607

[33] Wang S,Shao P.Exfoliation of covalent organic frameworks into few-layer redox-active nanosheets as cathode materials for lithium-ion batteries.J Am Chem Soc2017;139:4258-61

[34] Vadiyar MM,Bae J.Imidazole linker-induced covalent triazine framework-ZIF hybrids for confined hollow carbon super-heterostructures toward a long-life supercapacitor.Carbon Energy2023;5:e344

[35] Sun R.Covalent triazine frameworks (CTFs): synthesis, crystallization, and photocatalytic water splitting.Chemistry2023;29:e202203077

[36] Liu M,Jin S.Covalent triazine frameworks: synthesis and applications.J Mater Chem A2019;7:5153-72

[37] Zhang Y.Recent advancements in the synthesis of covalent triazine frameworks for energy and environmental applications.Polymers2018;11:31 PMCID:PMC6401784

[38] Wang K,Wang X.Covalent triazine frameworks via a low-temperature polycondensation approach.Angew Chem Int Ed2017;56:14149-53 PMCID:PMC5698698

[39] Liu M,Ding X.Controlling monomer feeding rate to achieve highly crystalline covalent triazine frameworks.Adv Mater2019;31:e1807865

[40] Evans J,Bruce PG.Electrochemical measurement of transference numbers in polymer electrolytes.Polymer1987;28:2324-8

[41] Chen Y,Pei H.Bioinspired separator with ion-selective nanochannels for lithium metal batteries.ACS Appl Mater Interfaces2023;15:18333-42

[42] Guo Y,Liu Y.An Autotransferable g-C₃N₄ Li⁺-modulating layer toward stable lithium anodes.Adv Mater2019;31:e1900342

[43] Zhang R,Chen X.Lithiophilic sites in doped graphene guide uniform lithium nucleation for dendrite-free lithium metal anodes.Angew Chem Int Ed2017;56:7764-8

[44] Zhou T,Choi JW.Lithium-salt mediated synthesis of a covalent triazine framework for highly stable lithium metal batteries.Angew Chem2019;131:16951-5

[45] Bai P,Brushett FR.Transition of lithium growth mechanisms in liquid electrolytes.Energy Environ Sci2016;9:3221-9

[46] Sand HJ.III. On the concentration at the electrodes in a solution, with special reference to the liberation of hydrogen by electrolysis of a mixture of copper sulphate and sulphuric acid.Lond Edinb Dublin Philos Mag J Sci1901;1:45-79

[47] Kim D,Yu B.Amine-functionalized boron nitride nanosheets: a new functional additive for robust, flexible ion gel electrolyte with high lithium-ion transference number.Adv Funct Mater2020;30:1910813

[48] Li L,Wang J.Asymmetric gel polymer electrolyte with high lithium ion conductivity for dendrite-free lithium metal batteries.J Mater Chem A2020;8:8033-40

[49] Ghazi ZA,Sun C.Key aspects of lithium metal anodes for lithium metal batteries.Small2019;15:e1900687

[50] Xiao J,Bi Y.Understanding and applying coulombic efficiency in lithium metal batteries.Nat Energy2020;5:561-8

[51] Zhang C,Shen J.Anion-sorbent composite separators for high-rate lithium-ion batteries.Adv Mater2019;31:e1808338