Cellulose Microcrystals with Brush-Like Architectures as Flexible All-Solid-State Polymer Electrolyte for Lithium-Ion Battery

Development of cellulose-based electrolytes can strongly reduce the cost of energy storage devices. However, the prepared cellulose-based electrolytes use high contents of liquid electrolytes, sacrificing the safety of the assembled cells. In this study, showcased as the first example in the field of cellulose-based all-solid-state polymer electrolytes (CSSPEs), we develop a flexible (stretchability >150%) SPE using a cellulose with brush-like architectures for lithium-ion batteries (LIBs). Specifically, to prepare the electrolyte matrix, ion-conducting segments are covalently connected onto the cellulose-based macroinitiator via living controllable polymerization. The CSSPE delivers good electrochemical performance. Especially, the ionic conductivity of the CSSPE reaches 8.00 × 10 –5 S cm –1 (30 °C) because the brush-like architectures are beneficial for the formation of more ion channels. The assembled LiFePO 4 /Li cell using the CSSPE exhibits excellent long cycle ability (over 450 cycles with a Coulombic efficiency of over 99%) and good rate capacity. The novel CSSPE with brush-like architectures provides possibility for preparing stretchable devices.