Enabling high-areal-capacity all-solid-state lithium-metal batteries by tri-layer electrolyte architectures

Abstract All-solid-state lithium-ion batteries (ASSLiBs) with metallic lithium (Li) anode, ceramic-type solid-state electrolyte (SSE) and nickel (Ni)-rich cathode offer great promise to deliver high energy density and high safety. However, the low cathode material loading and poor metallic Li/SSE interface are two major challenges. Herein, we design a new tri-layer SSE structure to address the challenges. A porous three-dimensional (3D) Li1·5Al0.5Ge1.5(PO4)3 (LAGP) layer acts as a host for LiNi0·8Mn0·1Co0·1O2 (NCM811) cathode, a thin but dense LAGP layer is employed to conduct ions and block dendrite, and a cross-linked solid-state polymer electrolyte (SPE) of polyethylene glycol bis(amine)-triglycidyl isocyanurate is introduced to the NCM811/LAGP/metallic Li interfaces to ameliorate contact issues. Enabled by such structure, the cathode loading in 3D porous LAGP layer reaches 13 mg cm−2, and delivers a reversible areal capacity of 2.01 mAh cm−2 at 0.1 C and a capacity retention of 70% over 50 cycles, whereas the conventional two-dimensional (2D) electrode only gives a low areal capacity of 0.11 mAh cm−2 and undergoes a rapid capacity fading. The significantly enhanced performance is ascribed to the continuous SSE structure and SSE/electrode interfacial compatibility. Our methodology on SSE construction design can provide a new strategy to develop the ASSLiBs with high energy density.