A high-performance rocking-chair lithium-ion battery-supercapacitor hybrid device boosted by doubly matched capacity and kinetics of the faradaic electrodes

Abstract

Battery-supercapacitor hybrid devices (BSHDs) are promising for certain applications requiring both high energy and power densities, but restricted by the electrolyte-consuming mechanism and imbalance of charge-storage capacity and electrode kinetics between battery-type and capacitor-type electrodes. Herein, a new prototype of rocking-chair lithium-ion BSHD with high energy and power densities is developed by employing pseudocapacitive T-Nb₂O₅ with a porous nanoflower structure as the anode and battery-type LiNi_0.815Co_0.15Al_0.035O₂ complexed in a three-dimensional interconnected conductive network as the cathode. Benefiting from the rational selection and optimization of the active material and electrode architecture, the anode and cathode exhibit exceptionally matched faradaic capacity and kinetics. Consequently, the BSHD delivers superior performance (165 W h kg⁻¹ at 105 W kg⁻¹ and 9.1 kW kg⁻¹ at 83 W h kg⁻¹) to previously reported rocking-chair BSHDs and could surpass the state-of-the-art electrolyte-consuming BSHDs at the device level. Therefore, this work will open a new avenue towards high-performance BSHDs.