有机添加剂改性的PEO基固态电解质

t present, organic electrolyte is one of the main components of commercial lithium-ion batteries, and its volatility and flammability greatly aggravate the safety hazards of lithium-ion batteries. With the rapid penetration of lithium-ion battery applications into all aspects of human society and the increasingly stringent requirements for lithium-ion battery safety in various application scenarios, the use of solid electrolytes instead of liquid electrolytes is an effective solution to the battery safety problem. Polyethylene oxide (PEO)-based electrolytes are potential candidates for solid-state electrolytes due to their high chemical stability, easy processability and good flexibility. However, PEO-based solid-state polymer electrolytes (PEO-SPEs) still suffer from poor mechanical strength, low ionic conductivity and narrow electrochemical window, which seriously limit the development space and application scope of PEO-SPEs. Therefore, in this thesis, a PEO-based hybrid polymer electrolyte (PEO-HPE) was designed using lithium-containing chain polymer lithium carboxymethylcellulose (CMC-Li) as an electrolyte additive to address the performance defects of PEO electrolytes. It was shown that the addition of CMC-Li effectively enhanced the mechanical and electrochemical properties of PEO-HPE, and its Young\'s modulus increased from 13.35 MPa to 102.90 MPa; the oxidation potential increased to 4.4 V, the lithium ion conductivity at 60 C increased by 2.4 times, and the Li+ migration number increased by 2.5 times. The LiFePO4 (LFP) solid-state battery based on the modified composite electrolyte showed a significant improvement in the multiplier performance, with the modified group providing a discharge specific capacity of 117.5 mAh-g-1 at a charge/discharge multiplier of 1C (the control group was only 30.1 mAh-g-1). In terms of cycling performance, the modified group has a capacity retention rate of 85.3% after 200 cycles at 0.5C (compared to 74.2% for the control group).