An interpenetrating network polycarbonate-based composite electrolyte for high-voltage all-solid-state lithium-metal batteries

The exploration of solid polymer-based composite electrolytes (SCPEs) that possess good safety, easy processability, and high ionic conductivity is of great significance for the development of advanced all-solid-state lithium-metal batteries (ASSLMBs). However, the poor interfacial compatibility between the electrode and solid electrolyte leads to a large interfacial impedance that weakens the electrochemical performance of the battery. Herein, an interpenetrating network polycarbonate (INPC)-based composite electrolyte is constructed via the in-situ polymerization of butyl acrylate, Li7La3Zr2O12 (LLZO), Lithium bis(trifluoromethanesulphonyl)imide, succinonitrile and 2,2-azobisisobutyronitrile on the base of a symmetric polycarbonate monomer. Benefiting from the synergistic effect of each component and the unique structure features, the INPC&LLZO-SCPE can effectively integrate the merits of the polymer and inorganic electrolytes and deliver superior ionic conductivity (3.56 × 10-4S cm-1 at 25 °C), an impressive Li+ transference number [t(Li+) = 0.52] and a high electrochemical stability window (up to 5.0 V vs. Li+/Li). Based on this, full batteries of LiFePO4/INPC&LLZO-SCPE/Li and LiNi0.6Co0.2Mn0.2O2/INPC&LLZO-SCPE/Li are assembled, which exhibit large initial capacities of 156.3 and 158.9 mAh g-1 and high capacity retention of 86.8% and 95.4% over 500 and 100 cycles at 0.2 and 0.1 C, respectively. This work offers a new route for the construction of novel polycarbonate-based composite electrolytes for high-voltage ASSLMBs.