Cobalt-doped Fe2O3@CoFe-layered double hydroxide heterostructures for enhanced supercapacitors and the oxygen evolution reaction

Abstract

Hematite (Fe₂O₃) is regarded as a promising material for supercapacitors due to its exceptional theoretical specific capacitance and structural adjustability. Nevertheless, the practical implementation of Fe₂O₃ is fundamentally constrained by its inherently low electrical conductivity. Herein, innovative cobalt-doped Fe₂O₃@CoFe-layered double hydroxide (LDH) heterostructures were fabricated via a secondary hydrothermal approach. Based on DFT calculations, Co doping and the formation of Co–Fe₂O₃@CoFe–LDH heterostructures effectively enhance electrochemical performance by optimizing the electronic structure and improving conductivity. The Co–Fe₂O₃@CoFe–LDH electrode exhibits high specific capacity (1202.2 F g⁻¹ at 1 A g⁻¹) and excellent cycling stability (71.93% after 3000 cycles). The asymmetric device delivers a high energy density of 41.47 Wh kg⁻¹ at 705.59 W kg⁻¹ and outstanding stability (74.72% after 3000 cycles). Moreover, the material exhibits exceptional OER catalytic activity with a lower overpotential of 255 mV at 10 mA cm⁻². Hence, this work offers fresh perspectives on the intentional doping of Co elements and coupled with heterostructure engineering for the controlled synthesis of integrated energy storage-catalysis devices.