Formatted PVDF in lamellar composite solid electrolyte for solid-state lithium metal battery

Solid polymer electrolytes (SPEs) hold great application potential for solid-state lithium metal battery because of the excellent interfacial contact and processibility, but being hampered by the poor room-temperature conductivity (∼ 10−7 S·cm−1) and low lithium-ion transference number $$({t_{{\rm{L}}{{\rm{i}}^ + }}})$$ . Here, a lamellar composite solid electrolyte (Vr-NH2@polyvinylidene fluoride (PVDF) LCSE) with β-conformation PVDF is fabricated by confining PVDF in the interlayer channel of -NH2 modified vermiculite lamellar framework. We demonstrate that the conformation of PVDF can be manipulated by the nanoconfinement effect and the interaction from channel wall. The presence of -NH2 groups could induce the formation of β-conformation PVDF through electrostatic interaction, which serves as continuous and rapid lithium-ion transfer pathway. As a result, a high room-temperature ionic conductivity of 1.77 × 10−4 S·cm−1 is achieved, 1–2 orders of magnitude higher than most SPEs. Furthermore, Vr-NH2@PVDF LCSE shows a high $${t_{{\rm{L}}{{\rm{i}}^ + }}}$$ of 0.68 because of the high dielectric constant, ∼ 3 times of that of PVDF SPE, and surpassing most of reported SPEs. The LiNi0.8Co0.1Mn0.1O2∥Li cell assembled by Vr-NH2@PVDF LCSE obtains a discharge specific capacity of 137.1 mA·hg−1 after 150 cycles with a capacity retention rate of 93% at 1 C and 25 °C. This study may pave a new avenue for high-performance SPEs.