Accelerating the Li-ion transmission of free-standing thick electrodes by using CMC-Li as ion-conducting binder

The growing demand for high energy density lithium-ion batteries (LIBs) has made the development of thick electrodes crucial. However, thick electrodes generally show poor rate capability due to the slow ionic transmission, which restricts their application. Herein, this work employed bacteria cellulose (BC) to fabricate free-standing thick LiMn2O4 (LMO) electrodes via vacuum filtration method combined with freeze-drying. Bacteria cellulose endowed thick electrodes with excellent flexibility and good mechanical strength. Simultaneously, Li+-conducting binder, that is carboxymethyl cellulose lithium (CMC-Li), was added to provide thick electrodes with promoted Li+ transmission and improved dynamic performance. The properties of CMC-Li were demonstrated in detail. Then, the structure and electrochemical performance of prepared free-standing thick electrodes were characterized systematically. More importantly, the mechanism of enhanced dynamic performance by CMC-Li was clarified clearly. This work paves a new way to prepare free-standing thick electrodes with high energy density and superior rate capability.