Transition Metal Oxides for Supercapacitors
S. Chandra Sekhar, Bhimanaboina Ramulu, Jae Su Yu
Abstract
Active materials are the core components of energy storage devices, which usually determine the potential window and capacity. Among the developed active materials, transition metal oxides (TMOs) have been fascinated as electrode candidates in supercapacitors (SCs) due to their high theoretical capacity, excellent redox chemistry, multivalence states, and affordable cost. In this chapter, firstly, different types of TMOs and their charge storage mechanism are discussed. Furthermore, combining the TMOs in a composite form leads to an improvement in the energy storage performance of SCs, and hence, different combinations of TMOs are elucidated broadly. The impact of hybridizing the different metal oxides with other materials like graphene, conductive polymers, etc. is also comprehensively discussed. On the other hand, versatile preparation methods to design the hierarchical/porous architectured nanostructures of TMOs are discussed in this chapter. Recently, metal–organic frameworks (MOFs) have emerged as a new class of materials and attracted a great deal of interest in a variety of fields because of their captivating features. This chapter also focussed on the development of highly porous MOF-based/derived TMOs and their contribution to the energy storage field. Considering next-generation flexible electronic gadgets, the proximity of TMOs in the fabrication of flexible energy storage devices is also described in this chapter.