Unlocking the potential of aluminium-ion hybrid capacitors: Advanced hybrid cathode for high-performance energy storage

The growing global energy demand and the imperative shift towards renewable energy sources have propelled advancements in energy storage technologies. Aluminium-ion hybrid capacitors (AIHCs) offer cost-effective, high-performance energy storage, but their performance relies on developing unique electrode materials with high energy density and long cycle life. In this study, a novel hybrid cathode material comprising MOF-5, boron nitride (BN), and carbon nanotubes (CNTs) was developed alongside a CNT-coated aluminium foil anode for AIHC applications. The synergistic integration of MOF-5's high surface area, BN's thermal and mechanical stability, and CNTs' excellent electrical conductivity resulted in a hybrid material with superior electrochemical properties. The assembled AIHC device (MOF-5/BN/CNT//Al) demonstrated a higher specific capacity of 175.1 mAh/g at 0.1 A/g than that of BN//Al (71.1 mAh/g) and MOF-5//Al (84.2 mAh/g). Furthermore, prominent diffusion contribution is observed in MOF-5/BN/CNT//Al due to enhanced charge transport kinetics. MOF-5/BN/CNT//Al device rendered high energy density of 140 Wh/kg, and a power density of 14.6 kW/kg. Furthermore, the device exhibited exceptional cyclic stability, retaining 92.2% of its initial capacity after 20,000 charge-discharge cycles. These findings highlight the potential of MOF/BN/CNT hybrids in advancing high-performance energy storage systems.