Electrolytes enriched by potassium perfluorinated sulfonates for lithium metal batteries

作     者：Shihan Qi Huaping Wang Jian He Jiandong Liu Chunyu Cui Mingguang Wu Fang Li Yuezhan Feng Jianmin Ma 戚世瀚;王华平;何健;刘建东;崔春雨;武明光;李芳;冯跃战;马建民

作者机构：School of Physics and ElectronicsHunan UniversityChangsha 410082China Key Laboratory of Materials Processing and Mold(Zhengzhou University)Ministry of EducationZhengzhou UniversityZhengzhou 450002China 

出 版 物：《Science Bulletin》 (科学通报（英文版）)

年 卷 期：2021年第66卷第7期

页      面：685-693,M0004页

核心收录：

学科分类：0808[工学-电气工程] 08[工学] 

基　　金：supported by the National Natural Science Foundation of China (11675051) the China Postdoctoral Science Foundation (2020M672477) the Key Research and Development Program of Hunan Province,China (2018GK2031) 

主　　题：Electrolyte Additives Lithium metal batteries Lithium anode protection Potassium perfluorinated sulfonates 

摘      要：Lithium(Li) metal is widely considered as a promising anode for next-generation lithium metal batteries(LMBs) due to its high theoretical capacity and lowest electrochemical potential. However, the uncontrollable formation of Li dendrites has prevented its practical application. Herein, we propose a kind of multifunctional electrolyte additives(potassium perfluorinated sulfonates) from the multi-factor principle for electrolyte additive molecular design(EDMD) view to suppress the Li dendrite growth. The effects of these additives are revealed through experimental results, molecular dynamics simulations and firstprinciples calculations. Firstly, K^(+)can form an electrostatic shield on the surface of Li anode to prevent the growth of Li dendrites. Secondly, potassium perfluorinated sulfonates can improve the activity of electrolytes as co-conductive salts, and lower the electro-potential of Li nucleation. Thirdly, perfluorinated sulfonate anions not only can change the Li^(+)solvation sheath structure to decrease the desolvation energy barrier and increase the ion migration rate, but also can be partly decomposed to form the superior solid electrolyte interphase(SEI). Benefited from the synergistic effects, an outstanding cycle life over250 h at 1 m A cm^(-2) is achieved in symmetric Li||Li cells. In particular, potassium perfluorinated sulfonate additives(e.g., potassium perfluorohexyl sulfonate, denoted as K+PFHS) can also contribute to the formation of high-quality cathode electrolyte interphase(CEI). As a result, Li||LiNi_(0.6)Mn_(0.2)Co_(0.2)O_(2) full cells exhibit significantly enhanced cycling stability. This multi-factor principle for EDMD offers a unique insight on understanding the electrochemical behavior of ion-type electrolyte additives on both the Li metal anode and high-voltage cathode.