Towards High Energy Density Li and Na Ion Batteries

Abstract

Modern life is moving towards a mobile and sustainable energy economy, in which rechargeable batteries play an essential role as a power supply. The current battery of choice is Li ion battery that is dominating the market but faces great challenges for future use mainly due to the demand for higher capacities and target for cost reduction. Next-generation rechargeable batteries such as Li-O2, Li-S and Na ion batteries, which offers higher capacities and cost-effectiveness, are being intensively researched as potential solutions to meet the future energy storage demand. 
This thesis focuses on the search of high-performance anode materials for both Li and Na ion batteries, including metallic Li and Na, Si, MgH2, and black P and Sn4P3 based composites. Various methods are involved to synthesize the active materials and electrodes in a cost-effective manner; and comprehensive characterization on the physico-chemical and electrochemical properties has been performed to provide fundamental understanding and insights into the electrochemical processes. This work has achieved long-lifespan and safe Li and Na metal anodes by suppressing the hazardous dendrite growth. The Si, P and MgH2 anodes presented in this work also exhibit high and stable electrochemical performance for Li and Na ion storage. Notably, the Na ion uptake in Si and MgH2 has been, for the first time, realized in experiments. This research shows great promise towards the commercial introduction of these anodes in next-generation high energy density Li and Na ion batteries.