Asymmetric supercapacitor comprising a core-shell TiNb2O7@MoS2/C anode and a high voltage ionogel electrolyte

Supercapacitors have emerged as appealing alternatives to rechargeable energy storage devices in renewable energy generation and storage systems due to their ultra-high power characteristics. However, their broad applications are hindered by their low energy density characteristic. Therefore, the designs of electrodes with high rate and high specific capacitance and electrolytes with wide-potential window are extremely crucial. A novel core–shell heterostructure, TiNb 2 O 7 as the core and C-encapsulated MoS 2 as the shell, was demonstrated. As a result of synergistic effects induced by the core–shell heterostructure, this nanoarchitectural anode exhibited a high rate capability and an excellent cyclic stability, 99% capacity was retented after 500 cycles. Moreover, a nanocomposite ionogel electrolyte composed of ionic liquid (IL), poly(vinylidene fluoride-co-hexafluoropropene)-hexafluoropropylene (PVDF-HFP) and SiO 2 was prepared. In our study, optimized solid lithium-ion capacitors (SLICs) exhibited an impressive energy density of 147.2 Wh kg −1 at 60 °C and an outstanding ultra-long term stability, 93.7% capacity was retented after 10,000 cycles at 1 A g −1 . These outstanding performances could be ascribed to the widened potential window and remarkable ionic conductivity of the ionogel electrolyte. The effective combination of nanoarchitectural anodes and a nanocomposite ionogel provides a novel and profound direction for the fabrication of highly safe and reliable solid lithium-ion capacitors with an enhanced high energy density.