Tailoring built-in electric field in cobalt sulfide/layered double hydroxide hollow heterostructured nanocages strung by MWCNTs for high-performance energy storage†

Layered double hydroxides (LDHs) and their hybrids exhibit excellent electrochemical properties in energy storage devices, but challenges like low conductivity and capacity degradation hinder their widespread use. To address these issues, we enhance the electrochemical performance of NiCo-LDH nanosheets by engineering a built-in electric field through strong interfacial interactions with Co₃S₄ nanoparticles. Co₃S₄/NiCo-LDH hollow heterostructured nanocages supported by functionalized multi-walled carbon nanotubes (SLFC) are synthesized. The F-MWCNTs serve as a structural scaffold and conductor, improving electron conduction and preventing aggregation. DFT calculations reveal an optimized electronic structure in SLFC with enhanced density of states near the Fermi energy level. SLFC demonstrates impressive electronic conductivity, a specific capacitance of 3092.69 F g⁻¹ (at 1 A g⁻¹), and an energy density of 105.32 W h kg⁻¹ (at 2.767 kW kg⁻¹) with excellent cycling stability, retaining 91.3% capacity after 10 000 cycles. This study offers a novel approach for modifying the electronic structure of LDH-based supercapacitors, advancing energy storage technologies.