Perspectives on chemistries of aqueous and non-aqueous batteries for renewable electricity storage

Abstract

The role of batteries towards mitigating the challenge of intermittent nature of solar and wind electricity supply cannot be over-emphasised. Batteries are essential complements to solar and wind electricity as we seek to increase the proportion of renewable electricity in the global energy mix. Since batteries are devices for chemical-electrical energy inter-conversion, their usefulness depends on chemistry. This makes it imperative to improve on the chemistries of existing commercial batteries for grid-scale electricity storage applications. In this contribution, we examined the chemistries of lead-acid, zinc-alkaline, lithium ion, aluminium and liquid metal batteries vis-à-vis their utility for grid-scale electricity storage. Simple assembly and rugged cell operation are key advantages of lead-acid batteries despite their low specific capacity. Poor cycle life span and low cell voltage are the main weaknesses of zinc-alkaline batteries. Emerging zinc ion batteries with improve cycle life span can make zinc-based batteries suitable for grid-scale applications. Lithium ion batteries are based on rocking chair chemistry and were an instant success for mobile and portable electronics application. Currently, lithium ion batteries are expanding into the electric vehicle applications and other areas. However, grid-scale application of lithium ion batteries will depend on cost and safety. Aluminium emerged from obscurity of Hall-Héroult electrolysis cell to a promising battery material. Emerging aluminium batteries can combine key strengths of zinc ion and lithium ion batteries to carve a sizeable market share including grid-scale application. Liquid metal batteries are grid-scale storage application focused. This battery type has advantages of simple assembly, low materials cost, and long cycle life span. However, high operating temperature and corrosion problems are its weaknesses.