Review: Transition metal oxides (RuO2, Co3O4, MnO2, and NiO) for pivotal electrode materials for high performance supercapacitors

Abstract

Because they offer quick energy storage, load-leveling, and grid stabilization, supercapacitors are essential to renewable energy applications. This paper highlights the substantial potential of supercapacitors in renewable energy applications and discusses their important advancements. Supercapacitors can benefit from high surface area, low cost, and high theoretical specific capacitance (3560 Fg⁻¹) of cobalt oxide (Co₃O₄) electrode materials. RuO2 can perform fast Faraday redox reactions and has a high theoretical capacitance of 2000 Fg⁻¹. Through quick surface - redox processes, cobalt (II,III) oxide (CoO₄) stores energy and frequently produces high specific capacitances more than 1100 Fg⁻¹. Transition metal oxide cobalt oxide has two direct optical band gaps (1.48 eV and 2.19 eV), making it an intrinsic p-type semiconductor. Because of its low cost, high theoretical capacitance (1387 Fg⁻¹), and environmental friendliness, manganese dioxide (MnO₂) is thought to be a perfect material for supercapacitors. A popular pseudocapacitive material for supercapacitors, nickel oxide (NiO) has a huge theoretical specific capacitance of about 2584 Fg⁻¹. With its strong redox activity, high theoretical capacitance, and affordability, nickel oxide (NiO) is a promising electrode material for energy storage. Pseudocapacitive electrode materials bridge the gap between high-power electric double-layer capacitors and high-energy batteries by storing energy through quick, reversible Faradaic surface redox processes.