A Novel Orientation Aliphatic Ketone‐Based Liquid Crystal Polymer Electrolyte for High‐Voltage Solid‐State Lithium Metal Batteries

Abstract Low room temperature ionic conductivity and interfacial incompatibility severely hinder the further application of polymer electrolytes in lithium metal batteries. Here, a novel shear‐oriented (SO) aliphatic ketone‐carbonyl‐based liquid crystal composite solid polymer electrolyte (FL 7 M 3 @CSPE SO ) is prepared by in situ thermal‐polymerization of liquid crystal monomer (FPZ‐LC, FL) and N, N' ‐Methylenebisacrylamide (MBA, M) on cellulose nanofiber (CNF) in the presence of triethylene‐glycol‐dimethyl‐ether (G 3 ) and lithium salt (lithium bis(trifluoromethanesulphonyl)imide, LiTFSI). The high polarity of keto‐carbonyl groups improves the dissociation ability of lithium salt. The highly oriented liquid crystals provide rapid ion transport channels. Thus, the FL 7 M 3 @CSPE SO achieves ionic conductivity of 10 −4 S cm −1 and a lithium‐ion transference number (t Li+ ) of 0.52 at 30 °C. Besides, in situ formed stable interface layer effectively inhibits the growth of lithium dendrites. The assembled Li/FL 7 M 3 @CSPE SO /Li cells operate stably over 5500 h at 0.05 mA cm −2 (30 °C). Impressively, the assembled Li/FL 7 M 3 @CSPE SO /NCM811 cells exhibits a long‐term cycle over 1200 h with a capacity retention of 92% under 0.05 C and 4.4 V (−5 °C). This work not only highlights the advantages of the aliphatic keto‐carbonyl groups and highly oriented liquid crystal in improving ion transport capacity, but also provides a design strategy for advanced polymer electrolytes suitable for lower temperature and high‐voltage solid‐state lithium batteries.