Tuning electrolyte enables microsized Sn as an advanced anode for Li-ion batteries

Abstract

Sn metal is believed to be one of the most promising alternative anodes to commercial graphite thanks to the high theoretical capacity and abundant storage. However, large volume change results in pulverization of the bulk electrode, which is more serious in microsized particles, leading to rapid capacity degradation. Therefore, microsized Sn was never successfully applied as the anode for Li-ion batteries. Herein, we report that the as-received Sn microparticles (325 mesh, or ∼45 μm) could be directly used as anodes for LIBs in 2.0 M LiPF₆ 2-MeTHF or 2.0 M LiPF₆ THF/2-MeTHF electrolyte, delivering a high capacity of ∼750 mA h g⁻¹, initial coulombic efficiency of >90%, average cycling coulombic efficiency of ∼99.9%, and capacity retention of 84.1% after 400 cycles at a rate of 2C. This work demonstrated that alloying anodes could be realized by exploring compatible electrolytes and forming compact SEI layers, representing a breakthrough for commercialization of LIBs based on alloying anodes.