Robust Electrochemical Performance of LIBs Using a Polymethylene-Based High-Density Carboxylic Acid Binder in Graphite Anodes

A durable electrochemical performance in lithium-ion batteries (LIBs) is increasingly important in future applications. Various strategies were used to develop functional binders for long cycles, high loading, and fast charging. However, despite constant efforts, the strategies mentioned above remain critically challenging and must be addressed. Herein, we utilized a nontoxic, water-soluble, and bioderived polymethylene-based binder containing a high concentration of carboxylic acid functional groups as side chains, demonstrating improved lithium-ion transport and minimizing electrolyte decomposition. Polymethylene's less flexible rod-like polymer architecture succeeds in exhibiting long cycling at 1 C with a specific capacity of 325 mAh g–1 and capacity retention of 79% at the 710th cycle. It also performed better fast charging behavior at 5 C with a specific capacity of 54 mAh g–1 and showed better rate and long cycling stability with high loading of graphite up to 3.4 mg cm–2. Hence, a poly(fumaric acid) binder enhances the LIB's electrochemical performance and mechanical strength.