Hierarchical MnCo2O4/NiMn Layered Double Hydroxide Composite Nanosheet Arrays on Nickel Foam for Enhanced Electrochemical Storage in Supercapacitors

Abstract

AbstractHerein, we report on layer‐by‐layer MnCo2O4/NiMn double hydroxide (LDH) nanosheet arrays (NAs) that are designed and synthesized by in‐situ growing the NiMn LDH NAs onto the surface of the MnCo2O4 NAs. The layer‐by‐layer architecture together with the synergistic effects between the NiMn LDH and MnCo2O4 components, substantially improves the energy storage performance of the composite NAs electrodes. The optimized composite NAs electrode exhibits a high specific capacitance of 3063 F g−1 at 3 A g−1 (four times with respect to the individual MnCo2O4 electrode), a capacitance retention of 2315 F g−1 at 30 A g−1, and a cycle stability with 94.7 % capacitance retention at 20 A g−1 over 5000 cycles. Moreover, an assembled MnCo2O4/NiMn LDH//active carbon (AC) asymmetric solid‐state supercapacitor (ASSC) is found to achieve a high energy density of 51.9 W h kg−1 at 806 W kg−1. These findings might offer a feasible strategy to synthesize the high‐performance MnCo2O4‐based composite electrodes for supercapacitors (SCs).