Controlling electric potential to inhibit solid-electrolyte interphase formation on nanowire anodes for ultrafast lithium-ion batteries

摘要

With increasing demand for high-capacity and rapidly rechargeable anodes, problems associated with unstable evolution of a solid-electrolyte interphase on the active anode surface become more detrimental. Here, we report the near fatigue-free, ultrafast, and high-power operations of lithium-ion battery anodes employing silicide nanowires anchored selectively to the inner surface of graphene-based micro-tubular conducting electrodes. This design electrically shields the electrolyte inside the electrode from an external potential load, eliminating the driving force that generates the solid-electrolyte interphase on the nanowire surface. Owing to this electric control, a solid-electrolyte interphase develops firmly on the outer surface of the graphene, while solid-electrolyte interphase-free nanowires enable fast electronic and ionic transport, as well as strain relaxation over 2000 cycles, with 84% capacity retention even at ultrafast cycling (>20C). Moreover, these anodes exhibit unprecedentedly high rate capabilities with capacity retention higher than 88% at 80C (vs. the capacity at 1C).