In Situ Formed Li3N Networks by Soft Carbon‐Si3N4 for Superior All‐Solid‐State Lithium‐Metal Batteries

Abstract The rapid growth of lithium (Li) dendrites has long hindered the development of all‐solid‐state lithium‐metal batteries (ASSLMB). Here, a composite soft carbon (SC)‐nano Si 3 N 4 (SiN) interlayer (SC‐SiN) is designed for in situ formation of Li 3 N network (with high ionic conductivity/diffusivity) after lithium embedding in nano‐Si 3 N 4, promoting the rapid migration of Li + and guiding the metal Li to be deposited uniformly in a 3D manner within the interlayer. It can solve the problem of rapid consumption of Li + and local charge accumulation at the interface of solid electrolyte and Li metal anode, thus avoiding the growth of Li‐dendrites. The resulting LCO/LPSCl/SC‐SiN‐Li ASSLMB achieves ultra‐high current density (12.5 mA cm −2 ) and ultra‐long cycle life (22 000 cycles with no degradation), as well as ultra‐high area capacity area capacity (15 mAh cm −2 ) and energy density (402.5 Wh kg −1 ), all of which break existing ASSLMB records. In addition, it is capable of 600 cycles at an areal capacity of 2.7 mAh cm −2 and 2 C (85.7% capacity retention). A pouch cell is also assembled to delivers high energy density (>320 Wh kg −1 ). These confirm the application potential of this configuration and are one of the most critical breakthroughs toward the commercialization of the ASSLMB.