Chapter 4 - Oxides free materials for symmetric capacitors

Abstract

Supercapacitors (SCs) are progressively used for energy transformation and storage systems in sustainable methodologies. SCs have attracted attention from many because of their storage capacity for a longer time and high energy density. This chapter presents scaled-down research on ongoing advancements of supercapacitor innovation. So far, the materials like spinel ferrites, e.g., MFe2O4, MMoO4, and MCo2O4 (where M denotes a transition metal ion), carbon materials, CPs, and transition metal sulfides (TMS) were used. Among these, TMS has fascinated considerable interest due to their distinctive electrochemical properties. It is because of the low charge-transfer resistance and high particle dispersion rate of metal sulfides. Composites made of TMS with CPs or graphite materials show the most elevated capacitance and cyclic steadiness. This is credited to oxygen and sulfur active sites that cultivate electrolyte penetration during cycling, making new active sites. The new advances in nanostructured metal sulfides with zero, one, two, and three-dimensional surface morphologies and blended metal sulfides for supercapacitor applications are discussed here. Apart from these, the recent advancement in emerged concept of integrating conductive matrices is also emphasized. This chapter summarizes recent developments in oxide-free materials for symmetric supercapacitor research and innovation, including a wide range of supercapacitor design methods utilizing different oxide-free materials and production approaches. At last, future advancements, forecasts, and difficulties in supercapacitor examination using oxide-free materials are also discussed.