An elastic cross-linked polymeric binder for high-performance Silicon/Graphite composite anodes in lithium-ion batteries

Si and graphite composite (Si/G) anodes are considered promising alternatives to traditional graphite anodes, providing a higher specific capacity and improved cycle performance for high-energy Li-ion battery applications. However, the practical application of composite electrodes has been hindered by the large volume expansion of the inner Si-based particles, which leads to interfacial instability and electrode structure disintegration. This paper presents a novel solution: a cross-linked polyvinyl alcohol (PVA)/malonic acid (MA) binder for Si/G composite electrodes, synthesized through a straightforward cross-linking process. This water-soluble crosslinked polymer binder, which incorporated a carboxylic acid crosslinker (1 wt.% MA and PVA (PM11)), demonstrated excellent adhesive and good elongation properties are significantly reduced the Si/G composite anode volume expansion compared with that of a commercial binder. The developed crosslinked polymer binder PM11 facilitated an 81.5% capacity retention after 200 cycles at 0.5 C-rate. These findings highlight the pivotal role of these novel carboxylic acid cross-linker binders (crosslinked polymer binders (PM11)) in the development of next-generation Li-storage devices, emphasizing the significant impact of this study on energy storage.