Recent Progress in the Core-Shell Nanostructures of the NiMoO4-Based Composite Materials for Supercapacitor Applications: A Comprehensive Review

Supercapacitors have emerged as one of the promising energy storage systems owing to their rapid charge/discharge capability, long-term cycling stability, and high power density. The application of core-shell nanostructures for supercapacitors is one of the effective strategies to achieve a high specific surface area for abundant reaction sites and good electrical conductivity for fast charge transfer, hence improving the performance of supercapacitors. Particularly, the use of NiMoO4 for the core-shell structure has drawn great attention due to its outstanding advantages, such as its natural abundance, low material cost, superior electrochemical performance, and wide electrochemical potential window in cyclic voltammetry. In this context, this review comprehensively covers the recent progress of the core-shell nanostructures based on the NiMoO4-composite materials, which find applications in supercapacitors. The composite materials that incorporate metal oxides such as NiMoO4, metal hydroxides, metal chalcogenides, carbon materials, and conductive polymers are discussed in detail for such core-shell nanostructures with the aim of understanding how the adopted materials and the relevant morphology govern the electrochemical features for supercapacitors. Finally, the existing challenges in current technologies for supercapacitors are discussed, while possible future directions in developing the NiMoO4-composite-based core-shell nanostructures are proposed for high-performance supercapacitors.