Study on the Directional Synthesis of Bi2S3 Induced by Graphene and the Mechanism of Pseudocapacitive Kinetics Regulation at the Interface

To address the issues of capacity decay and poor rate performance of Bi 2 S 3 anode materials, which are caused by their intrinsically low conductivity and significant volume expansion during cycling, this study adopts a redox self-assembly strategy. Under mild hydrothermal conditions, oxygen-containing functional groups on the surface of graphene oxide (GO) induce the directed growth of Bi 2 S 3 along the [001] crystallographic direction, successfully constructing a Bi 2 S 3 /GO composite anode with strong interfacial coupling. This structure effectively suppresses the agglomeration of Bi 2 S 3 nanorods, forms a 3D conductive network, alleviates volume strain, and avoids structural damage caused by traditional high-temperature sulfidation processes. Electrochemical tests show that the 1.0-Bi 2 S 3 /GO composite retains a capacity of 300 mAh·g −1 after 100 cycles at a current density of 100 mA·g −1 . At a high rate of 5000 mA·g −1 , it still exhibits a reversible capacity of 198.62 mAh·g −1 , and after current recovery, the capacity rapidly increases to 439 mAh·g −1 , with a capacity retention rate exceeding 70%. The lithium-ion diffusion coefficient reaches 8.7×10 −1 2 cm 2 ·s −1 , which is 2.8 times higher than that of the pure phase. Mechanistic analysis reveals that the characteristic peak (τ = 0.3 s) in the distribution relaxation time (DRT) relaxation spectrum corresponds to the pseudocapacitive behavior on the GO surface, with a contribution rate of 58% at a scan rate of 2 mV·s −1 , significantly optimizing the ion storage dynamics at the interface. Additionally, the built-in electric field at the interface facilitates charge transfer, effectively shortening the relaxation time. The synergistic π-π stacking buffering network further enhances structural stability and reaction reversibility. This study, through the “directed growth-pseudocapacitance regulation-relaxation matching” triple mechanism, provides new insights for the design of high-performance sulfide-based anodes. Graphical