A dual hydrogen bond crosslinking strategy for black phosphorus-based anodes in high rate capability lithium-ion batteries

Abstract

Black phosphorus (BP) has advantages over silicon and graphite in high-capacity fast charging. However, BP faces challenges such as low conductivity and volume expansion. Although composites of BP and graphite (G) can alleviate these problems to a certain extent, it is difficult to maintain the high performance of batteries at high current densities with conventional single binder systems. In this study, an innovative dual hydrogen bonding cross-linking strategy is proposed. The study used a cost-effective ball milling method to prepare BP-G composites and a hydrogen-bonded crosslinked polyacrylic acid (PAA)-poly(ethylene oxide) (PEO) binder to form hydrogen bonds with the BP. Hydrogen bonding cross-linking allows the binder to form a network structure, which effectively disperses the stresses. Hydrogen bonding exists between the binder and the BP. Ether bonds in the binder improve ionic migration. The degree of hydrogen bond crosslinking was optimized by adjusting the binder composition. The electrode material with the optimal binder ratio exhibited a discharge capacity of 1186 mAh g⁻¹ at 8 ​A ​g⁻¹. After 900 cycles, a reversible capacity of 771.8 mAh g⁻¹ was maintained, with a capacity retention rate of 65.1 ​%, significantly outperforming electrodes using polyvinylidene fluoride (27.9 ​%) and PAA (19.3 ​%).