Plasma-assisted and room-temperature construction of NiCo-LDH/CNT composite with the superior electrochemical performance

Nickel-cobalt layered double hydroxide (NiCo-LDH) possesses abundant redox-active sites and high theoretical capacity but suffers from poor conductivity and structural instability. Carbon nanotubes (CNTs), with high electrical conductivity and a large specific surface area, provide robust conductive networks and mechanical reinforcement. To combine these advantages, three-dimensional NiCo-LDH/CNT composites are rapid synthesized via an assisted liquid-phase plasma electrolysis method, aiming to construct efficient and stable electrodes for high-performance supercapacitors. Structural characterizations analysis confirm the uniform growth of ultrathin NiCo-LDH nanosheets on interconnected CNT frameworks, generating hierarchical porosity and abundant accessible active sites. Benefiting from this architecture, the composite delivers a high specific capacitance of 1856.4 F‧g⁻¹ at 1 A‧g⁻¹, with 87.5% retention at 10 A‧g⁻¹. An asymmetric device achieves an energy density of 39.3 Wh‧kg⁻¹ at a power density of 424.7 W‧kg⁻¹ and retains 90.5% capacitance after 10,000 cycles. Moreover, the flexible solid-state device exhibits stable charge–discharge behavior under various bending states. The outstanding capacitance, rate capability, and cycling stability highlight their promise for practical deployment in high-power energy-storage systems, wearable electronics, and grid-level buffering applications. These results demonstrate the effectiveness of assisted liquid-phase plasma electrolysis in rapidly constructing advanced composites for high-rate supercapacitors.