3D hierarchical oxygen-deficient AlCoNi-(oxy)hydroxides/N-doped carbon hybrids enable efficient battery-type asymmetric supercapacitor

Polynary transition-metal layered hydroxides are promising energy materials owing to their unique architecture, impressive theoretical capacities, and adjustable compositions. Regulating the dimensional morphology and active sites/redox states are the keys to electrochemical performance enhancement. Distinguish from the reported mono-metal or binary-metal configurations, a new ternary-metal AlCoNi-LTH is coanchored onto a highly graphitized porous N-doped carbon matrix to develop superior 3D hierarchical microporous functional energy hybrids AlCoNi-LTHs/NAC. The constructed hybrids possess superior structural durability, good electrical conductivity, and rich active sites due to the strong interfacial conjunction and favorable synergistic effect between the doped porous carbon and AlCoNi nanosheets. Consequently, the AlCoNi-LTHs/NAC hybrids demonstrate high conductivity, reasonable specific surface area, and superior specific capacitance, and the assembled hybrid battery-type supercapacitor reveals an ideal energy density of 72.6 Wh kg⁻¹ at a power density of 625 W kg⁻¹, which is superior to the reported devices. This strategy opens a platform to rationally design polynary transition-metal layered hydroxides and their hybrids for efficient supercapacitors.