A carbonized polymer dot-functionalized 3D conductive network binder for high-performance silicon anodes

Abstract

The practical application of silicon anodes in lithium-ion batteries is limited by their severe volume expansion and poor electrical conductivity. In this work, with epichlorohydrin (ECH) as a crosslinking agent, conductive carbonized polymer dots (CPDs) are in situ chemically crosslinked with carboxylated chitosan (CS) and xanthan gum (XG) to form a three-dimensional conductive network binder (CXDE). This binder, featuring abundant polar functional groups, not only facilitates electron transfer, but also significantly enhances adhesion to silicon. Remarkably, the Si/CXDE anode exhibits excellent electrochemical performance even without additional conductive additives, achieving a high initial capacity of 2832.6 mA h g⁻¹ and retaining 85.2% of its capacity after 100 cycles. This performance is significantly superior to that of Si/PAA anodes prepared by a common method with Super P as the conductive additive (initial capacity: 2275.8 mA h g⁻¹, the capacity retention rate after 100 cycles: 50.4%).