Corn Cob‐Derived Carbon‐Modified NiFe Layered Double Hydroxides as Electrode Material for Supercapacitors

Biomass waste is a potential source of energy storage materials. Herein, a biomass‐based carbon (CSC) is prepared using postconsumption corn cobs as the precursor through a solvothermal carbonization strategy. This carbon is further utilized to improve nickel–iron layered double hydroxide (NiFe LDHs) to enhance its electrochemical energy storage capacity. As a result, the specific capacitance of NiFe LDHs is significantly increased to a value of 1775 F g⁻¹ at a current density of 1 A g⁻¹, after the addition of CSC. This remarkable improvement indicates the broad application prospects of biomass waste in the field of energy storage and paves the way for the development of environmentally friendly and sustainable energy materials. Additionally, the asymmetric supercapacitor assembled with CSC/NiFe LDHs‐15 and AC electrodes exhibits an outstanding energy density of 15.6 Wh kg⁻¹ and a power density of 961.9 W kg⁻¹, representing a significant enhancement compared to traditional supercapacitor systems. After 10 000 charge–discharge cycles at a high current density of 10 A g⁻¹, it still retains 64.47% of its capacity. The excellent electrochemical performance and stability of this electrode material highlight the great potential of biomass waste in electrochemical energy storage.