A multi-step charging/discharging protocol enables stable cycling for lithium argyrodite-based all-solid-state lithium batteries

Abstract

Using sulfide solid electrolytes is considered a viable strategy for developing all-solid-state lithium metal batteries. However, the parasitic interfacial reactions between the electrolyte and the lithium anode and lithium dendrite growth inside the electrolyte have not been completely resolved. Herein, we proposed a multi-step constant-current charging/discharging (MCCCD) protocol on the basis of the regulation of a series of Li_7−xPS_6−xCl_x (x = 1.0, 1.3, 1.5, and 1.7) electrolytes with different chloride contents to reduce the damage to the lithium metal anode and further improve the cycle performance of the all-solid-state battery. The chlorine content has a significant impact on the stability of the Li/solid electrolyte interface. Specifically, the highest critical current density and lowest polarization were obtained for moderate chlorine content (Li_5.5PS_4.5Cl_1.5), which could be attributed to the effect of LiCl. Moreover, the multi-step constant-current charging/discharging (MCCCD) protocol can effectively alleviate the interface deterioration without any interface modification. The full cell with MCCCD maintains a reversible capacity of 140.1 mA h g⁻¹, with a capacity retention of 77.1% after 300 cycles. This work may provide a new strategy to enhance the electrochemical performance of all-solid-state lithium metal batteries.