Pulse Charge Suppressing Dendrite Growth at Low Temperature by Rapidly Replenishing Lithium Ion on Anode Surface.

ABSTRACT

Dendrite growth of lithium (Li) metal anodes is considered as one of the most tough issues for Li metal batteries with a theoretically high energy density. This is attributed to the rapid exhaustion of Li ions at the electrode/electrolyte interface, which is even worse at low temperatures with poor diffusion kinetics of Li ions. Here, pulse charge with intermittent rest time during battery charging is proposed to handle the dendrite growth issue of Li metal anodes at low temperatures. The depleted Li ions near the interfaces can be rapidly replenished during the rest time, thus effectively suppressing the dendrites growth. Further investigations indicate that the large dendrites can be suppressed at the Li ion nucleation stage. The equivalent lifespan considering the rest time is proposed. At -10oC, the lifespan of Li||Li batteries cycled under 3 mA cm-2 and 1 mAh cm-2 is increased from 24 h to equivalent 64 h. Li ||LiNi0.5Co0.2Mn0.3O2 batteries with 80% capacity retention can be stably operated from 39 cycles to 56 cycles. This design presents an efficient and convenient strategy to regulate the deposition behaviors of Li metal anodes with a dendrite-free morphology.