Improved flexible Li-ion hybrid capacitors: Techniques for superior stability

Flexible power devices play an increasingly crucial role in emerging flexible electronics. To improve the electrochemical performance of flexible power devices, novel electrode structures and new energy-storage systems should be designed. Herein, a novel flexible Li-ion hybrid capacitor (LIC) is designed based on an anode comprising Li₄Ti₅O₁₂ nanoplate arrays coated on carbon textile (LTO/CT) and a cathode comprising a flexible N-doped graphene/carbon-nanotube composite (NGC) film. The LTO/CT anode is fabricated by directly growing Li₄Ti₅O₁₂ nanoplates on CT with robust adhesion using a simple one-pot hydrothermal reaction. Considering the volume of a real-device flexible LIC, the NGC//LTO/CT configuration delivers high volumetric energy and power densities of 2 mWh·cm⁻³ and 185 mW·cm⁻³, respectively. Furthermore, the flexible LIC shows excellent flexibility and electrochemical stability, with extremely small capacity fluctuation under different bending states. This work demonstrates a scalable route to assemble flexible LICs as high-performance power devices.