Double-helix-superstructure aqueous binder to boost excellent electrochemical performance in Li-rich layered oxide cathode

摘要

Li-rich layered oxides are highlighted as promising candidates for the next-generation cathode materials in Li-ion batteries, but suffer from poor cycling stability and voltage fading during the cycling process. Currently, less efforts are devoted to addressing these issues through exploring novel binders. In this work, we explore an aqueous binder of xanthan gum with double helix superstructure containing abundant charged functional groups. This unique structure is beneficial to the occurrence of significant mechanical interlocking effect and formation of chemical bond with particles' surface, which can effectively suppress electrode exfoliation, particle pulverization and structural degradation during cycling. As a consequence, the electrode with xanthan gum still delivers the discharge capacity of 275.6 mAh g(-)(1) with the retention of 98.4% after 200 cycles at 0.1C rate. Accordingly, the mid-point discharge voltage remains 87% (about 2.3 mV/per cycle drop). The current study provides a useful insight into how to design and develop superior binders based on charged double-helix superstructure for potential low-cost and environmentally friendly aqueous processing of high energy density Li-ion batteries.