Liu Xiaofei, Wang Dong, Zhang Zibo, Li Gaunwu, Wang Jian, Yang Guangmin, Lin Hongzhen, Lin Jianyan, Ou Xing, Zheng Weitao
Key Laboratory of Automobile Materials of MOE, School of Materials Science and Engineering, and Jilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy Materials, Jilin University, Changchun, 130013, P. R. China.
Engineering Research Centre of the Ministry of Education for Advanced Battery Materials, School of Metallurgy and Environment, Central South University, Changsha, Hunan, 410083, P. R. China.
Small. 2024 Nov;20(45):e2404879. doi: 10.1002/smll.202404879. Epub 2024 Aug 5.
Traditional ethylene carbonate (EC)-based electrolytes constrain the applications of silicon carbon (Si-C) anodes under fast-charging and low-temperature conditions due to sluggish Li migration kinetics and unstable solid electrolyte interphase (SEI). Herein, inspired by the efficient water purification and soil stabilization of aquatic plants, a stable SEI with a 3D desolvation interface is designed with gel polymer electrolyte (GPE), accelerating Li desolvation and migration at the interface and within stable SEI. As demonstrated by theoretical simulations and experiment results, the resulting poly(1,3-dioxolane) (PDOL), prepared by in situ ring-opening polymerization of 1,3-dioxolane (DOL), creates a 3D desolvation area, improving the Li desolvation at the interface and yielding an amorphous GPE with a high Li ionic conductivity (5.73 mS cm). Furthermore, more anions participate in the solvated structure, forming an anion-derived stable SEI and improving Li transport through SEI. Consequently, the Si-C anode achieves excellent rate performance with GPE at room temperature (RT) and low temperature (-40 °C). The pouch full cell coupled with LiFePO cathode obtains 97.42 mAh g after 500 cycles at 5 C/5 C. This innovatively designed 3D desolvation interface and SEI represent significant breakthroughs for developing fast-charging and low-temperature batteries.
传统的碳酸亚乙酯（EC）基电解质由于锂迁移动力学缓慢和固体电解质界面（SEI）不稳定，限制了硅碳（Si-C）负极在快速充电和低温条件下的应用。在此，受水生植物高效水净化和土壤稳定作用的启发，采用凝胶聚合物电解质（GPE）设计了一种具有三维去溶剂化界面的稳定SEI，加速了界面处和稳定SEI内锂的去溶剂化和迁移。理论模拟和实验结果表明，由1,3-二氧戊环（DOL）原位开环聚合制备的聚（1,3-二氧戊环）（PDOL）形成了一个三维去溶剂化区域，改善了界面处的锂去溶剂化，并产生了具有高锂离子电导率（5.73 mS cm）的非晶态GPE。此外，更多的阴离子参与溶剂化结构，形成阴离子衍生的稳定SEI，并改善锂通过SEI的传输。因此，Si-C负极在室温（RT）和低温（-40°C）下与GPE配合时具有优异的倍率性能。与磷酸铁锂正极耦合的软包全电池在5 C/5 C下循环500次后，容量为97.42 mAh g。这种创新设计的三维去溶剂化界面和SEI代表了快速充电和低温电池开发的重大突破。
