Great Challenges and New Paradigm of The In Situ Polymerization Technology Inside Lithium Batteries

Abstract In situ polymerization technology is expected to empower the next generation high specific energy lithium batteries with high safety and excellent cycling performance. Nevertheless, the large‐scale commercial applications of most reported in situ polymer electrolytes are still full of challenges. Owing to the severe parasitic reactions caused by residual monomers, additional initiators and oligomers, lithium batteries using in situ polymer electrolytes often demonstrate limited specific capacity, poor cycling performance, and insufficient rate capability. However, this issue has not received adequate attention in previous reports. Furthermore, the design and evaluation of in situ polymer electrolytes still lack effective guidance and unified standards. Herein, the development history of in situ polymer electrolytes are systematically reviewed and critically disclose the great challenges. Then, from the aspects of monomers, initiators, separators, manufacturing technologies, safety and cycle life evaluation, unprecedentedly a new paradigm is provided for upgrading the in situ polymerization technology inside lithium batteries. It is hoped the novel paradigm will prompt much more insightful studies, expediting the commercialization of in situ polymerization technology in lithium batteries.