物理化学学报2025，Vol.41Issue(8)：103-114,12.DOI:10.1016/j.actphy.2025.100087
无碳酸乙烯酯电解液定向构筑正极电解质界面相实现高电压钴酸锂的宽温域稳定运行
Tailored cathode electrolyte interphase via ethylene carbonate-free electrolytes enabling stable and wide-temperature operation of high-voltage LiCoO2
摘要
Abstract
Raising the charge cut-off voltage of LiCoO2(LCO)cathodes provides a straightforward approach to increasing the energy density of lithium-ion batteries(LIBs).However,when the charge cut-off voltage exceeds 4.55 V(vs.Li/Li+),the cathode-electrolyte interphase(CEI)becomes unstable,failing to protect the LCO cathode from severe interfacial side reactions and structural instability.These issues accelerate battery degradation and severely hinder the practical application of high-energy-density LIBs.Moreover,ethylene carbonate(EC)-based electrolytes exhibit more pronounced parasitic reactions than EC-free electrolytes under high voltage,further exacerbating performance limitations.Therefore,optimizing the components and structure of the CEI with EC-free electrolytes remains a challenge.In this work,we aim to construct a robust and chemically stable F-/B-containing CEI on the surface of LCO cathodes using an EC-free electrolyte design.By replacing EC with more anti-oxidative propylene carbonate(PC)and fluoroethylene carbonate(FEC)co-solvents,the oxidative stability of the electrolyte is significantly improved.This promotes the formation of LiF within the CEI,thereby enhancing its mechanical strength.Meanwhile,the introduction of the sacrificial film-forming additive lithium bis(oxalato)borate(LiBOB)facilitates the generation of oxalates(Li2C2O4)and B-containing crosslinked polymers(LiBxOy)within the CEI.These components exhibit high electrochemical stability and flexibility,compensating for the limitations of the LiF-rich CEI and further enhancing the overall structural stability of the CEI.This combination results in a rigid-flexible coupling architecture composed of inorganic-rich components(LiF and Li2C2O4)embedded in B-containing crosslinked polymers(LiBxOy),ensuring both mechanical integrity and chemical stability of the CEI.Consequently,this tailored CEI effectively mitigates interfacial layer cracking and regeneration,reducing irreversible structural degradation and interfacial side reactions in high-voltage LCO cathodes.Based on these improvements,the EC-free PC-based electrolyte enables superior performance of LCO cathodes at 4.6 V,achieving 82%capacity retention at 0.5C over 200 cycles.Furthermore,graphite||LCO full cells demonstrate enhanced cycling stability at 4.5 V and enable operation across a wide temperature range(-40 to 80 ℃),highlighting the effectiveness of the rigid-flexible coupling CEI derived from the tailored electrolyte.By moving away from conventional EC-based electrolyte formulas,this work provides new insights into designing high-performance,wide-temperature,and sustainable PC-based electrolytes.关键词
高电压电解液/无碳酸乙烯酯电解液/添加剂/钴酸锂/正极-电解质界面相Key words
High-voltage electrolyte/Ethylene carbonate-free electrolyte/Additive/Lithium cobalt oxide/Cathode electrolyte interphase分类
化学化工引用本文复制引用
彭羽,陈嘉威,殷悦,曹永杰,廖莫愁,王丛笑,董晓丽,夏永姚..无碳酸乙烯酯电解液定向构筑正极电解质界面相实现高电压钴酸锂的宽温域稳定运行[J].物理化学学报,2025,41(8):103-114,12.基金项目
The project was supported by the National Natural Science Foundation of China(21935003).国家自然科学基金(21935003)资助项目 （21935003）
