SUMMARY

Organic materials with redox-active oxygen functional groups are of great interest as electrode materials for alkali-ion storage due to their earth-abundant constituents, structural tunability, and enhanced energy storage properties. It is considered a promising candidate to overcome the challenges associated with conventional inorganic electrode materials including high cost, limited natural reserves of rare earth metals, and environmental impact. However, the deficient charge conductivity and poor structural integrity in electrolyte solution significantly limited the utilization of organic materials as cell components in electrochemical energy storage systems. Therefore, it is critical to design a highly conductive and stable organic framework for the development of next-generation organic batteries. Here, I propose to systematically investigate the electrochemical properties of selected organic structures in alkali-ion batteries and apply the findings to improve the organic material design and charge storage optimization.
In preliminary studies, a 3D defective graphene structure and a hybrid carbon framework consisting of reduced graphene oxide and oxygen-functionalized carbon quantum dots (CQDs) were synthesized via the solvothermal reduction method. The modifications upon reduced graphene oxide were found to induce significant differences in physical and chemical aspects of the carbon structure, and systematic studies were undertaken to investigate their redox mechanism and enhanced electrochemical properties with Li-, Na-, and K-ions. By the same design principle, selected 2D covalent organic frameworks (COFs) with carbon backbone that are highly porous and flexible in molecular design are also being designed and synthesized. Based on the preliminary results, the proposed studies are to develop optimized graphene/COF material for charge storage and to further explore the application of 2D COFs as a protective layer in alkali-metal batteries.