A rapid and scalable fabrication of flexible P/C-CNTs anodes for sodium-ion battery

Flexible sodium-ion batteries (SIBs) are a prior energy supply for the future wearable electronic devices. And red phosphorus (P) with high theoretical capacity (2596 mAh/g) is regarded as an optimal candidate for SIB anode. However, the huge volume expansion of red P during the sodiation/desodiation process deteriorates the structural integrity of electrodes, resulting in the rapid capacity fading, which hinders the successful deployment of red P in the flexible SIB anodes. Herein, we propose a rapid and scalable method to fabricate the flexible P-based electrodes, which is similar with the common blade-coating method. The three-dimensional carbon nanotubes (CNTs) matrix from monodispersed CNT solution with robust mechanical strength ensures the structural integrity of the flexible electrode during the long cyclic process. As a result, the flexible P/C-CNTs electrode using as SIB anode delivers a reversible capacity (calculated based on the whole mass of the electrodes, 35 wt% P in electrode) of 442 mA h g(-1) at 0.5 A g(-1) after 100 cycles, together with 83 % capacity retention. And this work could propel the practical application process of flexible SIB.