Multifunctional gel polymer electrolyte suppressing lithium dendrites and stabling cathodes by asymmetric structural design.

[Display omitted] • An asymmetric gel polymer electrolyte (a-GPE) was well-designed via incorporating BTO and h-BNNS into PVDF-HFP nanofiber membrane. • The introduction of BTO and h-BNNS promoted the dissociation of lithium salts and further improved the ionic conductivity and Li-ion transference number. • The a-GPE effectively suppressed lithium dendrites and stabilized the cathodes simultaneously. • The Li/NCM-523 battery with a-GPE showed excellent rate performance and cycling stability. Lithium metal batteries with high-voltage cathodes are promising next-generation high performance energy storage devices. However, the lithium dendrites in lithium metal anodes, the unstable interface between electrolytes and high-voltage cathodes have hampered the application of high-voltage lithium metal batteries. Here, an asymmetric bilayer composite gel polymer electrolyte (GPE) was designed and prepared by introducing barium titanate (BTO) and hexagonal boron nitride nanosheets (h-BNNS) to PVDF-HFP matrix via electrospinning. The layer doped with h-BNNS was toward lithium metal to suppress the growth of lithium dendrites, and the layer doped with BTO was near to LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM-523) cathode to stabilize the cathode electrolyte interface (CEI) simultaneously. The bilayer GPE co-doped with h-BNNS and BTO not only improved the ionic conductivity to 3.77 × 10−3 S cm−1, but also ameliorated the cycle performance of lithium batteries. The Li/NCM-523 battery with asymmetric composite GPE showed excellent rate performance and cycling stability (151 mAh g−1 at 0.5 C, maintain 80% capacity after 170 cycles). Furthermore, the Li/LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM-811) battery with the asymmetric composite GPE exhibited the initial discharge capacity of 186.4 mAh g−1 and 81% of capacity retention after 100 cycles at 0.5 C. This work demonstrates that the asymmetric composite GPE is of promising application value in lithium metal batteries matched with high voltage cathodes. [ABSTRACT FROM AUTHOR]