Interface engineering by gelling sulfolane for durable and safe Li/LiCoO_(2) batteries in wide temperature range

环丁砜凝胶化界面工程助力安全耐用的宽温域Li/LiCoO_(2)电池

Lithium-metal batteries(LMBs)with high energy densities have aroused intensive interest in electrical energy storage devices but suffer from the risk of thermal runaway,especially under harsh conditions of high temperature or thermal abuse.Pursuing intrinsically thermally stable electrolytes with higher performance and higher safety beyond commercial liquid electrolytes is a major challenge in this field.Here we report on a unique,highly durable sulfolanebased gel electrolyte constructed by a facile gelling strategy.This method takes advantages of thermotolerant sulfolane as a plasticizer and strong dipole-dipole interactions to achieve the gelation of polymer polyvinylidene fluoride/polyethylene oxide.We systematically investigated the influence of gelled sulfolane on gel formation,lithium plating/stripping,and solid electrolyte interphase.Benefiting from favorable interface engineering,the sulfolane-based gel electrolyte remarkably enhances the cyclic and safety performances of LMBs.When used in the Li/LiCoO_(2) battery,the resulting gel electrolyte enables long-term cycling stability at high temperatures up to 90°C.Moreover,the thermal safety of practical Li/LiCoO_(2) pouch cells(up to 190°C)has also been demonstrated by accelerating rate calorimetry.These results contribute to the development of high-safety LMBs that require abuse tolerance,high energy,and long calendar life.

高能量密度锂金属电池在电化学储能领域受到了广泛关注,但其存在热失控的风险.尤其在高温或热滥用等恶劣条件下,安全隐患更加凸显.研发本征热稳定、高安全电解质是该领域的一个主要挑战.在该工作中,我们提出了一种简单易操作的凝胶化策略,制备出独特的、高热稳定的环丁砜基凝胶电解质.采用耐高温环丁砜作为增塑剂,通过强偶极-偶极相互作用,实现了聚偏氟乙烯/聚环氧乙烷基质之间的凝胶化,并系统地研究了砜基凝胶对凝胶化过程、锂沉积/剥离和固态电解质界面的影响.由于良好的界面特性,砜基凝胶电解质显著提高了锂金属电池的长循环和安全性能.由凝胶电解质组装的Li/LiCoO_(2)电池,在高温(高达90℃)条件下仍然呈现出优异的循环稳定性.此外,通过加速量热仪证实了Li/LiCoO_(2)软包电池的高热安全性(>190℃).该研究工作为开发耐滥用、高比能和长寿命的高安全性锂金属电池提供了新方法.