Room Temperature Synthesized Hybrid Open Frameworks for Li-Ion Battery Cathodes

Abstract

Li-ion batteries (LIBs) have been the most promising battery technology owing to their large energy density, environmental friendliness and design flexibility. LIBs have been dominating the rechargeable battery market fue to their advantages and they found application in various electonic gadgets. Large scale utilization of LIBs is anticipated in the near future for efficient utilization of renewable energy as there is gap between energy supply and demand. As solar radiation is available during daytime, the peak energy demand is at night. In addition, LIBs are expected to push forward the production of eco-friendly transportation such as electric vehicles (EVs) and hybrid electric vehicles (HEVs). Transformation from conventional vehicles to EVs are mainly hindered by the high upfront price of the EVs which are mainly due to the high cost of the battery packs used to power these vehicles. Hence, cost reduction of LIBs is one of the major strategies to bring forth the EVs to compete in the market with their gasoline counterparts. In our attempt to produce cheaper high-performance cathode materials for LIBs, a Graphene/MOPOF (Metal Organophosphate Open Framework) [1-3] nanocomposite with ~4 V of operation has been developed by a cost effective room temperature synthesis that does not require any expensive post-synthetic treatments at high temperature in inert atmospheres like Ar/Ar-H2. These open frameworks has a layered structure with each layer made of metal phosphate cross-linked by oxalate. Presence of alkali ions in the interlayer space with a redox system helpes in the reversible extraction of them, making it a feasible cathode material. Though the pristine material undergoes reversible lithium storage, there was capacity fading. Enhanced lithium cycling with minimal capacity fading was witnessed with the graphene nanocomposite owing to the increased electronic conductivity and enhanced Li diffusivity. Stable reversible capacity of ~100 mAh g-1 were obtained. Refereces A. Shahul Hameed, M. V. Reddy, M. Nagarathinam, Tomče Runčevski, Robert E Dinnebier, Stefan Adams, B. V. R. Chowdari and Jagadese J. Vittal, Sci. Rep., 2015, 5, 16270. A. Shahul Hameed, M. Nagarathinam, Martin Schreyer, M. V. Reddy, B. V. R. Chowdari and Jagadese J. Vittal, J. Mater. Chem. A, 2013, 1, 5721-5726. M. Nagarathinam, K. Saravanan, E. J. H. Phua, M. V. Reddy,B. V. R. Chowdari and J. J. Vittal, Angew. Chem., Int. Ed., 2012, 51, 5866–5870.