Black Phosphorus/Nanocarbons Constructing a Dual-Carbon Conductive Network for High-Performance Sodium-Ion Batteries

Black phosphorus has been recognized as a prospective candidate anode material for sodium-ion batteries (SIBs) due to its ultrahigh theoretical capacity of 2596 mA·h/g and high electric conductivity of ≈ 300 S/m. However, its large volume expansion and contraction during sodiation/desodiation lead to poor cycling stability. In this work, a BP/graphite nanoparticle/nitrogen-doped multiwalled carbon nanotubes (BP/G/CNTs) composite with a dual-carbon conductive network is successfully fabricated as a promising anode material for SIBs through a simple two-step mechanical milling process. The unique structure can mitigate the effect of volume changes and provide additional electron conduction pathways during cycles. Furthermore, the formation of P–O–C bonds helps maintain the intimate connection between phosphorus and carbon, thereby improving the cycling and rate performance. As a result, the BP/G/CNTs composite delivers a high initial Coulombic efficiency (89.6%) and a high specific capacity for SIBs (1791.3 mA·h/g after 100 cycles at 519.2 mA/g and 1665.2 mA·h/g after 100 cycles at 1298 mA/g). Based on these results, the integrated strategy of one- and two-dimensional carbon materials can guide other anode materials for SIBs.