Single-ionic conductive quasi-solid-state electrolyte membranes based on nematic liquid crystal polymer network

The self-assembled ordered structure of liquid crystal polymer networks (LCNs) can construct specific channels through the LC molecular orientation, benefitting the ordered transport of Li ions. Meanwhile, single-ion conducting polymer electrolytes can effectively enhance the safety of lithium-ion batteries by raising the lithium transference number ( t Li + ) and preventing the growth of lithium dendrites. Herein, Li salt grafted nematic LCN was coated on poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) membrane to make NLCN-Li/Pv and NLCN-Li/Pv/N composite membranes according to the single- or double-sided way. After coupling with plasticizer, quasi-solid-state electrolyte membranes have been successfully produced. The electrochemical tests disclosed that they possessed benign thermal stability and electrolyte/electrode compatibility. The high t Li + over 0.7 indicated their near single-ion conductive characteristic. A small amount (0.5 M) of extra Li salt added to the plasticizer could effectively improve the ion conductivity ( σ ) while the t Li + remained around 0.7. Moreover, the doping of silica nanoparticles into the NLCN-Li layer furtherly increased the σ up to 1.5 × 10 −4  S cm −1 while the t Li + rose to 0.88. The assembled LFP|Li cells also showed outstanding cycling stability and rate capabilities, indicating the applicability of the composite electrolyte membrane and providing insights into the design and preparation of ordered quasi-solid-state electrolytes for high-performance and safe secondary batteries.