Silicon Nanospheres Supported on Conductive MXene Nanosheets as Anodes for Lithium-Ion Batteries

Silicon (Si) anodes are expected to be employed in future for lithium-ion batteries (LIBs), due to their high capacity. However, the main challenge is to assemble Si with conductive materials to increase the conductivity and stability of Si anodes. In this work, we optimized a method to prepare Si nanoparticles (NP)/MXene anode materials for LIBs via electrostatic assembly of positively charged Si nanospheres, coated with poly-diallyl dimethyl ammonium chloride, and negatively charged MXene nanosheets, which increase the number of active sites for strong Si NP attachment and minimize both restacking of MXene nanosheets and Si NP aggregation. The Si NP/ MXene anodes have a capacity of 1917.9 mA h g-1 after 300 charge/discharge cycles at 0.5 A g-1. The electrochemical characterization of Si NP/MXene nanocomposite shows high energy storage, cycle stability, and rate performance. Optimization of Si/MXene composites can improve their performance as anode materials for high energy density LIBs.

Automated summary

Silicon (Si) anodes are expected to be used in lithium-ion batteries (LIBs) in the future due to their high capacity. However, the main challenge is to assemble Si with conductive materials to improve the conductivity and stability of Si anodes. This study optimized a method to prepare Si nanoparticles (NP)/MXene anode materials for LIBs through electrostatic assembly of positively charged Si nanospheres coated with poly-diallyl dimethyl ammonium chloride and negatively charged MXene nanosheets, which increased the active sites for Si NP attachment and reduced restacking of MXene nanosheets and Si NP aggregation. The Si NP/MXene anodes exhibited a capacity of 1917.9 mA h g-1 after 300 charge/discharge cycles at 0.5 A g-1, indicating high energy storage, cycle stability, and rate performance. Optimization of Si/MXene composites can enhance their performance as anode materials for high energy density LIBs.