Novel High Energy Density Sodium Layered Oxide Cathode Materials - from Material to Cells

Abstract

Lithium ion batteries have now been commercially available for the past twenty-five years. There has been a steady improvement in lithium ion battery technology throughout this period and lithium ion batteries are widely considered as the technology of choice to meet the energy demands of the future. However, there is growing research and commercial interest in other metal-ion battery technologies that could also meet certain areas of future energy demand. Sodium-ion technology has commanded an increasing research and commercial interest over recent years due to the high abundance and uniform distribution of sodium across the world, and the reported potential commercial advantages of lower cost, greater sustainability and improved safety characteristics of sodium ion batteries compared with their lithium-ion counterparts. Sharp Laboratories of Europe Ltd have been developing a new sodium ion cell chemistry based upon a tin-containing nickel based layered oxide cathode and a hard carbon anode. Here we report on the challenges faced during the development of a new sodium-ion technology in moving from a new electrode material, through from half cell results to small full cell development and then larger scale full cell development. We discuss the optimisation of the material choice, electrolyte, electrode parameters and formation process on the gravimetric and volumetric cell energy density along with the lifetime and rate behaviour of the cells.