Crystallographic oriented plating by using lithiophilic ionic additives in carbonate electrolyte for enabling high voltage lithium metal batteries

Abstract

The practical utilizations of high voltage (>4.0 V) lithium (Li) metal batteries are severely hindered by the unstable solid electrolyte interphase (SEI) and uncontrolled growth of dendritic Li in carbonate electrolyte. In this work, lithiophilic active ionic additives (In(NO3)3, lithium difluoro(oxalate)borate (LiDFOB), and LiNO3) are adopted to generate a multi-layer SEI in commercial carbonate electrolyte and promote the preferential Li plating along the (200) direction. As evidenced theoretically and experimentally, it is found that In(NO3)3 ionic additive generates a lithiophilic In-containing inner SEI layer, which induces the oriented Li plating along the (200) plane and a low surface energy of deposited Li. In addition, the LiDFOB additive is used to obtain LiF-rich middle SEI to improve the interfacial energy of SEI, and the LiNO3/tetramethylene sulfone (TMS) additive generates a Li3N-rich outer SEI to accelerate Li+ transport. As a result, the modified carbonate electrolyte can ensure the Li (50 μm) ‖LiNi0.8Co0.1Mn0.1O2 full cell to realize an ultra-high average CE of 99.3 % and a high-capacity retention of 94.2 % after 100 cycles. This work reveals the mechanism of multi-layer SEI induced crystallographic oriented Li plating and the internal mechanism of Li+ transport, and provides a simple approach to bring Li metal into practical high voltage Li metal batteries.