SODIATION MECHANISMS IN SI, GE, AND SN FOR NA-ION BATTERY ANODES: A FffiST PRINCIPLES STUDY

摘要

Lithium-ion batteries (LIBs) currently dominate the electrical energy storage market for portable applications. However, with the enormous demand for LIBs as a major power source in electronics and vehicles, the availability of Li resources and rising price become a daunting concern, which leads to the search for different energy storage systems in parallel. Among the possible alternatives, sodium (Na), located right below Li in the periodic table, has an electrochemical Na/Na~+ redox potential only 0.3 V above that of Li/Li~(+1). Also, Na is widely abundant and costs much less than Li, which offers great advantage targeting large-scale and stationary storage applications. Experimentally, group IV elements (Si, Ge, and Sn) have been well studied as anode materials for LIBs, but the evaluation of their application in NIBs has just begun both experimentally and theoretically. In this work, we use DFT calculations to examine and compare the sodiation behaviors of Si, Ge, and Sn.