Alloy-type and conversion-type anode materials for enhanced performance as lithium ion battery anode materials

Charge storage in the contemporary lithium-ion battery is at an energy density too low to support the function of long-range electric vehicles and other electronically powered technologies. To obtain up to two times or greater higher energy density than what is available by intercalation of lithium ions into graphite, the prevalent anode material in commercial batteries, materials with a higher storage density of lithium may be used, including materials that alloy with lithium or undergo a reversible conversion reaction to form lithium oxide. In this work, several such materials are considered – Ge, SnO2, Co3O4, and Ge0.1Se0.9 – and focus is directed to first demonstrating significantly enhanced cycling stability and capacity retention at variable charge/discharge rates and, second, to explaining the electrochemical performance in terms of key physical and chemical properties. Particular attention is given to assessing the formation of the solid electrolyte interphase (SEI) formed upon the anode material during charge/discharge cycling by means of microscopy and chemical characterization.