Stable composite electrolytes of PVDF modified by inorganic particles for solid‐state lithium batteries
Ren‐Jie Pei, Tian-Yuan Song, Yeali S. Sun, You-Fen Li, Ru Yang
Abstract
Abstract Polymer electrolytes have been attracting much attention because of their flexibility and easy follow‐up processing, but their Li + conductivity in lithium‐metal batteries (LIBs) is unsatisfactory. Stable composite electrolytes of poly (vinylidene fluoride) (PVDF) polymer with high lithium‐ion conductivity have been prepared by a trigger structural modification of Li 6.5 La 3 Zr 1.5 Nb 0.25 Ta 0.25 O 12 (LLZNTO) garnet ceramic and TiO 2 oxide. The influences of various amounts of TiO 2 and LLZNTO on electrochemical performance were systematically examined. These composite electrolytes exhibited maximal Li + conductivity of 2.89 × 10 −4 S cm −1 , which is consistent with the value of pure ceramic electrolytes. Furthermore, it possessed the stable long‐term Li cycling and the wide electrochemical window, involving repeated Li plating/stripping at 0.2 mA cm −2 over 280 h without failure. The discharge specific capacity and Coulomb efficiency for all‐solid‐state LIBs assembled with these membranes delivered outstanding cycling stability with high discharge capacities (117.9 mA h g −1 ) at 0.1 C rate and Coulomb efficiency reached 99.9% after 25 cycles. The high Li + conduction capability can be ascribed function of introducing TiO 2 and LLZNTO to restrain tremendously the crystalline behavior of the polymer. Furthermore, the LLZNTO can be complex with PVDF for dehydrofluorination, and it can also offer a burst transportation route for lithium ions. This system might serve as an attractive use for polymer solid electrolytes and open up new possibilities for safe all‐solid‐state LIBs.