锂离子电池正极材料过渡金属离子溶出的危害及抑制研究

Study on the Detriment and Inhibition of the Dissolution of Transition Metal Ions in Cathode Materials of Lithium-Ion Batteries

含锂过渡金属氧化物正极材料在循环过程中,特别是高温和高电压条件下,其界面的过渡金属离子会部分溶解到电解液中。已有学者报道通过对正极材料进行包覆、掺杂等改性手段或通过调控电解液组分的方法来稳定电极/电解液界面,以抑制过渡金属离子的溶出,但目前尚未找到完全抑制溶出的方法。溶出的过渡金属离子会迁移并沉积到负极界面,增加界面阻抗;残留在电解液中的过渡金属离子还会降低电解液的热稳定性。简要综述了过渡金属离子溶出引起电池性能衰退的机制和抑制策略,希望引起更多科学家对过渡金属离子对负极和电解液的危害以及抑制研究的重视,为设计新型电解液体系和电解液添加剂提供思路和建议。

During the cycling process,the transition metal ions in the lithium transition metal oxide cathode will partially dissolve into the electrolyte especially under high temperature and high voltage conditions.It has been reported that the transition metal ion dissolution can be inhibited by modifying the cathode material through coating,doping,as well as manipulation of electrolyte composition,to stabilize the electrode/electrolyte interface.However,a method to completely inhibit its dissolution has not yet been found.The dissolved transition metal ions will migrate and deposit at the anode interface,resulting in increased interface impedance;while the residual transition metal ions in the electrolyte will promote thermal decomposition of the electrolyte,thereby reducing its thermal stability.The study briefly reviews the mechanisms causing battery performance degradation during the migration and deposition of dissolved transition metal ions,as well as the suppression strategies.We aim to raise awareness among scientists regarding the detrimental effects of transition metal ions on the negative electrode and electrolyte and stimulate research on inhibition methods.The findings can provide insights and suggestions for the future design of novel electrolyte systems and electrolyte additives.