Robust and flexible polymer/MXene-derived two dimensional TiO2 hybrid gel electrolyte for dendrite-free solid-state zinc-ion batteries

Gel electrolytes are key components for flexible energy storage devices. However, disadvantages such as poor ionic conductivity and mechanical behavior limit the practical applications of gel electrolytes. Herein, two-dimensional TiO2 nanosheets are fabricated from Ti3C2Tx MXene by a one-step hydrothermal reaction. The structure and component of Ti3C2Tx MXene can be easily controlled by modulating the synthesis conditions. Influences of TiO2 nanosheets content in PVA-based gel electrolyte are explored, which brings higher ionic conductivity and better mechanical properties with suitable additive amount. As a consequence, with the hybrid gel electrolyte, highly stable Zn plating/stripping is achieved (over 3000 h at 0.5 mA cm−2). Full Zn||PVA-Zn(CF3SO3)2-TiO2||V2O5 cell shows high capacity (216 mAh g−1 after 115 cycles) and excellent cycling performance. This work provides an alternative route to develop high performance hybrid gel electrolyte for flexible energy storage devices such as Li/Na/K/Zn and supercapacitors.