低温磷酸铁锂电池用全醚高熵电解液的设计研究

Design and research of all-ether high-entropy electrolyte for low-temperature lithium iron phosphate batteries

磷酸铁锂材料在常温下展现出优异的循环稳定性和能量密度,但低温性能受到了其低离子电导率和缓慢动力学的严重限制。本文利用具有不同溶剂化能力的醚类溶剂设计了一种新型的全醚高熵电解液,以提高磷酸铁锂电池在低温条件下的电化学性能。实验结果表明,该策略可有效提高电解液在低温环境下的离子导电率和改善动力学稳定性,从而提高磷酸铁锂电池的低温放电容量和循环寿命。在低温(-20℃)环境下,本工作所设计的电解液展现出了出色的充放电稳定性。经过150次循环测试后,其容量保持率高达99.7%,且在低温下仍可保持室温容量的81.1%,并具有效性和普适性。这一新的策略提升了磷酸铁锂电池的低温性能和应用范围。

Lithium iron phosphate(LFP)materials are known for their outstanding cycle stability and energy density at room temperature(RT,25℃);however,their performance at low temperatures(LT,-20℃)is hindered owing to poor ionic conductivity and sluggish kinetics.This study introduces a novel all-ether high-entropy electrolyte,formulated by integrating ethers of varying solvating powers,to enhance the electrochemical performance of LFP batteries at LT.Experimental results confirm that this approach considerably enhances the ionic conductivity and kinetic stability of the electrolyte at LT,thereby substantially improving the low-temperature discharge capacity and cycle lifespan of LFP batteries.The mix-7 electrolyte variant,in particular,demonstrates exceptional charge-discharge stability at LT.After 150 cycles,it retains a high capacity retention rate of 99.7%and maintains 81.1%of its initial capacity at RT.This strategy proves effective and versatile,markedly enhancing the low-temperature performance and broadening the application spectrum of LFP batteries.