Suppressing lithium dendrite growth by a synergetic effect of uniform nucleation and inhibition

Abstract

The lithium dendrites issue presents a major challenge limiting the commercialization of Li metal anodes for high-energy-density batteries. Herein, an AgPF₆–LiNO₃ hybrid electrolyte additive was introduced into a carbonate electrolyte, which was found to induce the formation of a homogeneous dense layer of Ag–Li alloy seeds with small sizes on the Li metal surface. The formation mechanism of such fine Ag–Li alloy seeds on the Li metal substrate was evaluated, which revealed an interesting synergistic effect between AgPF₆ and LiNO₃. The occurrence of such a dense layer of Ag–Li alloy seeds was found to play a significant positive role in homogeneous nucleation and growth of Li dendrites, and LiNO₃ could inhibit the growth of Li and act as a grain refiner during a repetitive plating/stripping process, thus enabling profoundly improved structural stability and excellent long-term cycle performance for the Li anode during the cycling process. With the co-presence of AgPF₆–LiNO₃ in the electrolyte, the relevant symmetric cells could work steadily for 3000 h with slight polarization at a density of 0.5 mA cm⁻²; and the Li–graphite battery can exhibit good cycle performances and deliver a specific energy density of 374 W h kg⁻¹ at a power density of 747 W kg⁻¹.