An Enhanced High-Rate NaV(PO)-NiP Nanocomposite Cathode with Stable Lifetime for Sodium-Ion Batteries.

Herein, we report on a high-discharge-rate NaV(PO)-NiP/C (NVP-NP/C) composite cathode prepared using a polyol-based pyro synthesis for Na-ion battery applications. X-ray diffraction and electron microscopy studies established the presence of NaV(PO) and NiP, respectively, in the NVP-NP/C composite. As a cathode material, the obtained NVP-NP/C composite electrode exhibits higher discharge capacities (100.8 mAhg at 10.8 C and 73.9 mAhg at 34 C) than the NVP/C counterpart electrode (62.7 mAhg at 10.8 C and 4.7 mAhg at 34 C), and the composite electrode retained 95.3% of the initial capacity even after 1500 cycles at 16 C. The enhanced performance could be attributed to the synergetic effect of the NiP phase and nanoscale NVP particles, which ultimately results in noticeably enhancing the electrical conductivity of the composite. The present study thus demonstrates that the NaV(PO)-NiP/C nanocomposite is a prospective candidate for NIB with a high power/energy density.