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 (similar to 10-(7) S.cm(-1)) and low lithium-ion transference number (tLi+). Here, a lamellar composite solid electrolyte (Vr-NH2@polyvinylidene fluoride (PVDF) LCSE) with beta-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 beta-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 x 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(Li+) of 0.68 because of the high dielectric constant, similar to 3 times of that of PVDF SPE, and surpassing most of reported SPEs. The LiNi0.8Co0.1Mn0.1O2Li 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 degrees C. This study may pave a new avenue for high-performance SPEs.