Constructing three‐dimensional hydrogen‐bonding network and porous film from chitosan enables high‐performance silicon@carbon anode

Abstract Anodes based on silicon@carbon (Si@C) composites are expected to be used in the next generation of commercial lithium‐ion batteries due to their high specific capacity and high element abundance. However, particle pulverization and falling off, caused by volume expansion and repeated rupture and formation of SEI on electrode surface, still hinder its industrialization. Herein, a three‐dimensional hydrogen‐bonding network and porous film structure are constructed from chitosan (CS), polyvinyl alcohol and polyvinylpyrrolidone to enable high‐performance Si@C anode in this work. The formed hydrogen‐bonding network can significantly improve the electrical conductivity. The unique porous film structure, owing to a high specific surface area, can increase the contact between the material and the electrolyte and effectively accommodate the expansion effect of the electrode during the cycle. After 800 cycles at the current density of 500 mA·g −1 , the reversible specific capacity remains at 945.8 mAh·g −1 . When testing rate performance, the specific capacity can still reach 522 mAh·g −1 under the current density of 2000 mA·g −1 and returns to 1126 mAh·g −1 at 100 mA·g −1 . The porous film material proposed in this work has a simple preparation method and excellent properties, which will provide useful provision for the industrial application of Si@C materials in the future.