(407d) Partially Carbonized Polymer Binder with Polymer Dots for Silicon Anodes in Lithium-Ion Batteries

Large-scale applications of conventional conductive binders for Si anodes in lithium-ion batteries are challenging to accomplish due to their complex synthesis steps and high cost. Herein, a carbonized polymer dots-assisted polyvinyl alcohol-chitosan (PVA-CS-CPDs) binder is developed through a simple and low-cost hydrothermal method. Through rational design, the PVA-CS-CPDs binder retains rich polar groups while forming conjugated structures. The conjugated structure endows the PVA-CS-CPDs with high electronic conductivity, and the retained polar groups maintain strong binding strength. The proposed water-soluble binding system acts as both binder and conductive additive, enabling stable cycling for high-Si-content (90 wt %) anodes without any other conductive additives. The silicon anode consisting of 90 wt% Si and 10 wt% PVA-CS-CPDs binder shows a high reversible capacity of more than 2000 mA h g^-1 after 200 cycles at a current density of 0.2 C and maintains an area capacity of 3 mAh cm^-2 for more than 100 cycles with high silicon loading of 3 mg cm^-2. Considering these advantages, CPDs-assisted polymer binders provide a new strategy for further increasing the content of Si or other active materials in electrodes.