Red phosphorus/Ti3C2 MXene nanocomposite and flexible free-standing electrode for sodium-ion storage

Red phosphorus (RP) has been recognized as a promising anode candidate for sodium-ion batteries (SIBs) due to its high theoretical capacity and natural abundance. However, the electrochemical performance of RP is restricted by the critical issues of the large volume variation upon cycling and the low intrinsic electronic conductivity. Herein, a nanocomposite with the structure of well-dispersed RP nanoparticles intimately attached to the surface of two-dimensional Ti3C2 nanosheets (NRP/Ti3C2) is prepared by a facile chemical precipitation method. The introduction of Ti3C2 nanosheets can effectively prevent the RP nano-grains/clusters from agglomeration and growth in the synthesis process. Besides, the flexible Ti3C2 sheets can not only function as the mechanical support for accommodating the volume change of RP upon Na+ uptake/release process, but also provide an efficient conductive network for electron transportation. Moreover, the shortened ions diffusion distance enabled by the nano feature of RP further favors the electrode reaction kinetics. When employed as anode for SIBs, the synthesized NRP/Ti3C2 composite exhibits a reversible capacity of ~862 and 576 mAh g-1 at 0.1 and 0.5 A g-1, respectively, as well as a maintained capacity of 525.2 mAh g-1 after 100 cycles at 0.1 A g-1. In addition, the fabricated free-standing NRP/Ti3C2 electrode with a capacity of ~2.21 mAh cm-2 and stable electrochemical cycling provides a valid guide toward high-performance RP-based anodes for realizing SIBs with high energy density.