Cationic surfactant assisted electrostatic self-assembly of nitrogen-rich carbon enwrapped silicon anode: Unlocking high lithium storage performance

Abstract

Nitrogen-rich carbon (N-rich-C) coating is attractive to enhance capacity, reduce resistance, and alleviate volume expansion of silicon anode in Li-ion batteries. However, the non-uniform coating of N-rich-C on silicon might restrict its optimum performance. In this study, poly(diallyldimethylammonium chloride) (PDDA) is employed as a cationic surfactant to tailor the surface potential of bare ball-milled Si particles, enabling the electrostatic self-assembly between Si particles and graphitic carbon nitride as the N-rich-C precursor. Continuous N-rich-C enwrapped ball-milled silicon (Si@N-rich-C) has been obtained after pyrolysis with a high N to C ratio of 0.65 and abundant pyridinic-N and pyrrolic-N, facilitating fast kinetic transport and accommodating more Li+ ion storage. Combined with the high capacity of Si, Li-ion cell with Si@N-rich-C electrode exhibits a high capacity of 1732 mAh g−1 after 200 cycles of charge-discharge at 400 mA g−1. At high-rate testing, Si@N-rich-C also maintains a high capacity of 1673 mAh g−1 at 1000 mA g−1. This study provides an effective approach for synthesizing high-capacity silicon anode for Li-ion batteries.