In situ formed Li${}_3$N networks by soft carbon-Si${}_3$N${}_4$ for superior all-solid-state lithium-metal batteries

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. (© 2024 Wiley‐VCH GmbH)