A synergistic vertical graphene skeleton and S-C shell to construct high-performance TiNb2O7-based core/shell arrays

Bespoke synthesis of wide-temperature high-power electrodes is of great importance for the development of advanced power-type lithium ion batteries (LIBs). Herein, we report a powerful combined solvothermal-electrodeposition (ST-ED) method to construct titanium niobium oxide (TiNb2O7) arrays sandwiched between a highly conductive vertical graphene (VG) skeleton and S-C shell forming a binder-free VG/TiNb2O7@S-C electrode. VG and S-C work cooperatively to establish an omnibearing conductive network on TiNb2O7 through internal and external integration. Positive advantages including large porosity, improved conductivity and enhanced structural stability are obtained in the VG/TiNb2O7@S-C core/shell arrays. Consequently, excellent electrochemical high-power performance at medium-high temperature (25 to 70 degrees C) is demonstrated for the designed VG/TiNb2O7@S-C electrodes, which show a high capacity from 284 to 354 mA h g(-1) at 1C, and 181 to 241 mA h g(-1) at 160C as the working temperature increases from 25 to 70 degrees C. Additionally, a remarkable high-temperature (70 degrees C) cycling span is proven for the VG/TiNb2O7@S-C electrode with a capacity of 203 mA h g(-1) at 40C after 5000 cycles. The synergistic positive effect from the VG and S-C shell is responsible for the enhancement of high-power capability. Our work paves the way for the fabrication of novel high-power electrodes for electrochemical energy storage.