Electron/ion-conductive and flexible dual-functional copolymer enabled by EDOT and h 2PDMS for optimized Li-ion batteries

作者：Jingwei Wang, Zhaowen Bai, Zejia Zhao, Guangping Zheng, Junye Cheng, Guohua Chen · 发表于：Nano Research Energy · 年份：2024 · DOI：10.26599/nre.2024.9120133 · 被引用次数：11 · 研究领域：Advancements in Battery Materials、Advanced Battery Materials and Technologies、Advanced Battery Technologies Research

Electron/ion-conductive flexible copolymer PEDOT-PDMS (poly(3,4-ethylenedioxythiophene)-poly(dimethylsiloxane)) was successfully developed, which not only effectively optimizes high-voltage NaLiFePO 4 F cathode through dripping on electrode surface but also improves high-capacity Si anode through in-situ polymerization on the surface of Si particles. Theoretical calculation and experiments indicate that π-π conjugated structure in PEDOT-PDMS molecular chains easily interacts with PF 6 – anions, providing electron transfer pathways and preventing HF production. Moreover, Li ions transfer through Si-O in the amorphous phase of the copolymer, and its Young’s modulus at rupture is 1.17±0.10 MPa. The in-situ TEM results directly confirm that the polymer layer provides conducting pathways and buffers the stress induced by lithiation. With the NaLiFePO 4 F coated cathode, the cells show good cycle stability (~100% of capacity retention after 500 cycles) and high chemical diffusion coefficient of lithium-ions (1.89×10 –9 cm 2 ·s –1 and 1.20×10 –9 cm 2 ·s –1 ). In the case of coated Si anode, a capacity of 1512 mAh·g –1 is retained after 1000 cycles at 0.5 C with a capacity retention of 69.8% in terms of the highest specific capacity around the 160 th cycle. This work opens a new avenue for the simultaneous optimization of cathode and anode with a functional polymer.