Li+ selective transport network-assisted high-performance of garnet-based solid electrolyte for Li metal batteries

Abstract

Battery systems based on garnet-type solid electrolytes and Li metal anodes coupled with high-specific-capacity cathodes are expected to be the most promising high-energy density solid-state lithium-ion batteries. However, the low critical current density of garnet-type solid electrolytes and their high interface resistance have been the main challenges facing these materials in the application of solid-state batteries. Herein, a low-melting-point metal chloride coating combined with in situ lithiation addresses the key issues of interface contact and growth of Li dendrites. BiCl₃ with fluid properties can serve as an “aqueous” interlayer, in situ constructing a 3D cross-linked Li⁺ selective transport network for Li⁺ transfer (BiLi₃) and electron blockage (LiCl) via thermal lithiation. Consequently, Li/Li symmetric cells can charge/discharge dendrite-free at a high current density of 10.0 mA cm⁻² and stably cycle at 2.5 mA cm⁻² for over 1000 h at room temperature. The Li metal full cells with coated garnet solid electrolyte and LiFePO₄ cathode exhibit a 105.5 mA h g⁻¹ residual capacity at a rate of 4C and 138.8 mA h g⁻¹ reversible capacity at 1C after 600 cycles. This innovative modification strategy laid the groundwork for future commercial applications of garnet-type solid electrolytes.