Feasible engineering of cathode electrolyte interphase enables the profoundly improved electrochemical properties in dual-ion battery

Dual-ion battery (DIB) composed of graphite cathode and lithium anode is regarded as an advanced sec-ondary battery because of the low cost, high working voltage and environmental friendliness. However, DIB operated at high potential (usually >= 4.5 V versus Li+/Li) is confronted with severe challenges in-cluding electrolyte decomposition on cathode interface, and structural deterioration of graphite accom-panying with anions de-/intercalation, hinder its cyclic life. To address those drawbacks and preserve the DIB virtues, a feasible and scalable surface modification is achieved for the commercial graphite cathode of mesocarbon microbead. In/ex-situ studies reveal that, such an interfacial engineering facilitates and reconstructs the formation of chemically stable cathode electrolyte interphase with better flexibility alle-viating the decomposition of electrolyte, regulating the anions de-/intercalation behavior in graphite with the retainment of structural integrity and without exerting considerable influence on kinetics of anions diffusion. As a result, the modified mesocarbon microbead exhibits a much-extended cycle life with high capacity retention of 82.3% even after 10 0 0 cycles. This study demonstrates that the interface modifica-tion of electrode and coating skeleton play important roles on DIB performance improvement, providing the feasible basis for practical application of DIB owing to the green and scalable coating procedures (c) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.