Double-Layer Electrolyte Boosts Cycling Stability of All-Solid-State Li Metal Batteries
Changlong Lei, Jingyi Li, Zhouliang Tan, Yue Li, Peipei He, Yuming Liu, Yunjiao Li, Feixiang Wu, Yi Cheng, Zhenjiang He
Abstract
All-solid-state lithium metal batteries (ASSLMBs), as a candidate for advanced energy storage devices, invite an abundance of interest due to the merits of high specific energy density and eminent safety. Nevertheless, issues of overwhelming lithium dendrite growth and poor interfacial contact still limit the practical application of ASSLMBs. Herein, we designed and fabricated a double-layer composite solid electrolyte (CSE), namely, PVDF-LiTFSI-Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 /PVDF-LiTFSI- h- BN (denoted as PLLB), for ASSLMBs. The reduction-tolerant PVDF-LiTFSI- h- BN (denoted as PLB) layer of the CSE tightly contacts with the Li metal anode to avoid the reduction of LATP by the electrode and participates in the formation of a stable SEI film using Li 3 N. Meanwhile, the oxidation-resistance and ion-conductive PVDF-LiTFSI- LATP (denoted as PLA) layer facing the cathode can reduce the interfacial impedance by facilitating ionic migration. With the synergistic effect of PLA and PLB, the Li/Li symmetric cells with sandwich-type electrolytes (PLB/PLA/PLB) can operate for 1500 h with ultralong cycling stability at 0.1 mA cm –2 . Additionally, the LiFePO 4 /Li cell with PLLB maintains satisfactory capacity retention of 88.2% after 250 cycles. This novel double-layer electrolyte offers an effective approach to achieving fully commercialized ASSLMBs.