Sandwich‐Structured Quasi‐Solid Polymer Electrolyte Enables High‐Capacity, Long‐Cycling, and Dendrite‐Free Lithium Metal Battery at Room Temperature
Qi Liu, Yongjie Dan, Miqiu Kong, Yanhua Niu, Guangxian Li
Abstract
Abstract The insufficient ionic conductivity, limited lithium‐ion transference number (t Li +), and high interfacial impedance severely hinder the practical application of quasi‐solid polymer electrolytes (QSPEs). Here, a sandwich‐structured polyacrylonitrile (PAN) based QSPE is constructedin which MXene‐SiO 2 nanosheets act as a functional filler to facilitate the rapid transfer of lithium‐ion in the QSPE, and a polymer and plastic crystalline electrolyte (PPCE) interface modification layer is coated on the surface of the PAN‐based QSPE of 3 wt.% MXene‐SiO 2 (SS‐PPCE/PAN‐3%) to reduce interfacial impedance. Consequently, the synthesized SS‐PPCE/PAN‐3% QSPE delivers a promising ionic conductivity of ≈1.7 mS cm −1 at 30 °C, a satisfactory t Li + of 0.51, and a low interfacial impedance. As expected, the assembled Li symmetric battery with SS‐PPCE/PAN‐3% QSPE can stably cycle more than 1550 h at 0.2 mA cm −2 . The Li||LiFePO 4 quasi‐solid‐state lithium metal battery (QSSLMB) of this QSPE exhibits a high capacity retention of 81.5% after 300 cycles at 1.0 C and at RT. Even under the high‐loading cathode (LiFePO 4 ≈ 10.0 mg cm −2 ) and RT, the QSSLMB achieves a superior area capacity and good cycling performance. Besides, the assembled high voltage Li||NMC811(loading ≈ 7.1 mg cm −2 ) QSSLMB has potential applications in high‐energy fields.