A carbon-doped anatase TiO2-Based flexible silicon anode with high-performance and stability for flexible lithium-ion battery

Flexible Si composite anodes consisting of mechanical anatase TiO2 robust buffer layer anchored on carbon cloth has been synthesized through the controllable in-situ sol-gel techniques. This novel TiO2 layers demonstrate the remarkable suppress ability to alleviate the silicon volume variation during the lithiation and delithiation process. As a result, the Si/TiO2-CC composite anodes exhibit the remarkable reversible areal capacity of 3.21 mA h/cm2 (1720 mA h/g of Si active particles) at the current density of 0.2 mA/cm2 and 1.82 mA h/cm2 (1380 mA h/g of Si active particles) at 3 mA/cm2, meanwhile, it can maintain the capacity retention of 94.5% after 100 cycles at 3 mA/cm2. Furthermore, an all-flexible battery based on Si/TiO2-CC anode and NCM811 cathode is also fabricated. The flexible battery shows excellent mechanical integrity and Si interface stability under continuous bending and twisting state, due to the “bridge” effect of TiO2 layer. Our work provides a new route to establish the silicon-based flexible anodes using high-modulus bonding materials to suppress silicon volume expansion.