A Multifunctional Polymer Binder for High-Performance Si/C Anodes in Lithium-Ion Batteries

Conventional poly(acrylic acid) binders are unable to satisfy the rigorous criteria for silicon anodes, which impedes the progress of high-energy-density lithium-ion batteries. Therefore, it is essential to design a binder capable of withstanding the volumetric impact and low electrical conductivity of Si-based anodes. In this study, a multifunctional binder, named the PODA binder, with a 3D polymer network structure was proposed to achieve enhanced mechanical properties and improved electronic and ionic conductivity based on amide bonds, phenyl ether bonds, and pi-pi interactions, effectively preserving the completeness of the Si anodes. The phenyl ether group facilitated rapid Li+ and electron transport, establishing efficient conduction pathways within the binder. The PODA binder successfully maintained the structural integrity and mitigated the volumetric expansion of the silicon-carbon anode electrodes. At 2 A g- 1, enabled by the binder, the Si-C anode achieved superior specific charge capacity retention of approximate to 65% (1303.1 to 850.1 mAh g- 1) after 300 cycles. In comparison, the control Si-C anode retained only approximate to 8.3% (1207.9 to 100.1 mAh g- 1) after 200 cycles. The strategy represents a pioneering method to construct high-performance and high-mass-loading Si-based electrodes for high-energy-density Li-ion batteries.