Synergistical Stabilization of Li Metal Anodes and LiCoO<sub>2</sub> Cathodes in High-Voltage Li∥LiCoO<sub>2</sub> Batteries by Potassium Selenocyanate (KSeCN) Additive
Ang Fu, Jiande Lin, Zhengfeng Zhang, Chuanjing Xu, Yue Zou, Chengyong Liu, Pengfei Yan, De‐Yin Wu, Yong Yang, Jianming Zheng
Abstract
Dramatic growth of lithium (Li) dendrite and structural deterioration of LiCoO2 (LCO) lead to rapid failure of a high-voltage Li∥LCO battery. The nitrile group (−C≡N) is beneficial to maintain the integrity of the LCO lattice due to its strong affiliation to Co ions, whereas the −C≡N bond is incompatible with the Li metal anode, leading to form a deleterious solid electrolyte interphase (SEI) film. Herein, a dual-functional electrolyte additive potassium selenocyanate (KSeCN) is introduced to construct stable and dense SEI/cathode electrolyte interphase (CEI) films by synergistic effects with −Se and −C≡N groups, resulting in uniform Li deposition and a stabilized LCO lattice during cycling. With a trace amount of KSeCN (0.1 wt %) in conventional carbonated electrolyte, the Li∥LCO battery exhibits promoted cycling performance at high charge cutoff 4.6 V. This work provides a strategic guidance for rational design of electrolyte to construct stable SEI and CEI films, to achieve a high-energy-density Li∥LCO battery with great performance.