Fig. 28. (a) CV curves of CuO, Cu₃N and Cu₃N@CoFe-LDH at a scan rate of 5 mV s⁻¹. (b) CV curves of Cu₃N@CoFe-LDH at various scan rates. (c) GCD curves of CuO, Cu₃N and Cu₃N@CoFe-LDH at a current density of 1 mA cm⁻². (d) GCD curves of Cu₃N@CoFe-LDH at various current densities. (e) Current density dependence of the areal capacitance, (f) Nyquist plots of EIS and (g) cycling performance of the pristine CuO, Cu₃N and Cu₃N@CoFe-LDH. Reproduced with permission from ref. 128. Copyright 2018 The Royal Society of Chemistry.