Oligomerized imide and thioimide organic cathode materials via a H-transfer mechanism for high capacity lithium ion batteries

Abstract

Organic cathode materials (OCMs), synthesized from abundant and renewable resources, could be the most promising cathode materials for next-generation high capacity lithium-ion batteries (LIBs) due to their inherent advantages of high specific capacity, low cost, and excellent safety. According to theoretical calculations, imide and thioimide could be two classes of high-capacity OCMs for LIBs since these OCMs could undergo H-transfer processes to generate reaction sites for lithium ion storage and facilitate the ultra-high storage capacity of cathode materials. In this work, we adopt cyanuric acid (CA) and trithiocyanuric acid (TTCA) as the imide and thioimide for cathode materials of LIBs. Based on the 6-electron storage mechanism, CA and TTCA have remarkable theoretical specific capacities of 1246 and 908 mA h g⁻¹, and experimentally deliver capacities of 464.6 and 820.6 mA h g⁻¹, respectively, at a current density of 500 mA g⁻¹ at room temperature. A H-transfer reaction mechanism was proposed and supported by ex situ Raman and XPS studies, electrochemical characterization, and NMR measurements. This work suggests that the H-transfer mechanism could be a promising pathway for the design and development of OCMs for high-capacity cathodes in high energy density LIBs.