Reversible lithium plating in the pores of a graphite electrode delivers additional capacity for existing lithium-ion batteries enabled by a compatible electrolyte

Abstract

It has always been our unrelenting effort to continuously enhance the energy density of lithium-ion batteries (LIBs). Energy density of LIBs is generally improved by optimizing the electrode materials and battery architecture. Increasing the energy density based on existing facilities and technologies is still considerably challenging. Herein, we propose a compatible electrolyte to purposely plate metallic lithium on graphite anode and widen the charging window to 4.6 V. It realizes highly reversible lithium plating/stripping behavior in the graphite anode pores. The graphite anode is transformed into a graphite/lithium hybrid anode, providing a significantly higher capacity than its nominal value. The optimized electrolyte enables conventional graphite||high-nickel layered cathode pouch cells to deliver 18 % increased energy density. It exhibits excellent compatibility with graphite and lithium, quick wettability and the ability to build a stable interface, all of which are essential for realizing high-energy–density hybrid anodes. Additional capacity can be further increased by reasonably tuning the porosity of the graphite anode. The improvement is easy to implement and works seamlessly with state-of-the-art manufacturing processes. This work demonstrates a cost-effective and facile approach to increasing the energy density of existing batteries.