Spinel NiCo2O4 based hybrid materials for supercapacitors: Recent developments and future perspectives

The growing need for energy storage devices has directed the development of supercapacitors (SCs) with higher power density and comparatively higher energy density. The characteristics of supercapacitors are critically influenced by the electrode materials. As a result, several studies have focused on generating new electrode materials for high-performance supercapacitors. Due to its remarkable benefits, including superior theoretical capacity, low cost, ecological abundance, and straightforward synthesis spinel NiCo2O4 as an electrode material for supercapacitors has gained increasing attention in recent years. However, subsequently, it's poor electrical conductivity and limited active surface area, NiCo2O4 constantly experiences structural and substantial capacity degradation. Therefore, a systematic and thorough review of the advancements in the current understanding of and ability to modify NiCo2O4-based electrode materials from a wide range of perspectives is required. The assembly and fabrication process of NiCo2O4-based electrode materials is thoroughly covered in this article. The main objective of this review article is to highlight recent developments in adopting the suggested methodologies to enhance the overall electrochemical performance including specific capacitance, rate capability and cycling stability of NiCo2O4-based electrode materials, considering synthesis, control of unique morphologies, and composite material design along with the fabrication techniques for spinel NiCo2O4-based nanomaterials with controlled topologies and various elaborated architectural designs. The benefits of NiCo2O4 as a material for supercapacitors are highlighted in the review, including its superior energy density, outstanding power density, rate competence and great cycle stability. We hope that this review will provide ample of information to the readers and will encourage more research and developments on the design of high-performance supercapacitors based on spinel-based transition metal oxides.