High-Rate-Capacity Cathode Based on Zn-Doped and Carbonized Polyacrylonitrile-Coated Na₄MnV(PO₄)₃ for Sodium-Ion Batteries

Abstract

Na4MnV(PO4)3 (NMVP) is a promising cathode material for sodium-ion batteries (SIBs) because of its extraordinary three-dimensional structure that provides plenty of channels for sodium-ion migration. However, the unsatisfied electrical conductivity of NMVP limits its utilization in SIBs. Herein, Zn-doped NMVP with a uniform carbonized polyacrylonitrile (PAN) coating layer, named NMZVP@cPAN, was synthesized via a sol–gel method, and carbonized PAN was uniformly distributed on the surface of NMVP. Therefore, the NMZVP@cPAN cathodes exhibited an outstanding discharge capacity of 70.6 mA·h·g–1 at 30 C and remarkable cycling stability with an admirable retention of 89.64% after 1000 cycles at 5 C. Rietveld refinement and ex situ X-ray diffraction analyses were performed to determine the change in the crystal structure. Density functional theory calculations were performed to determine the effects of Zn doping on the density of states and the migration energy barriers. Finally, the NMZVP@cPAN cathodes were successfully modified and could be used in SIBs as NMVP cathodes.

Synergistic Strain Suppressing and Interface Engineering in Na4MnV(PO4)3/C for Wide-Temperature and Long-Calendar-Life Sodium-Ion Storage

“…Fourier-transform infrared reflection (FTIR) spectra further confirm that five materials were successfully synthesized without any impurities, as shown in Figure S3a. Peaks are seen at 540/620, 580/1010/1060/1090, and 1160 cm –1 , originating mostly from the stretching vibrations of M–O, P–O, and OP–O bonds. , Moreover, the carbon contents of NMVP/C and NMVZP/C-0.05 as determined by thermogravimetric analysis are ∼9.1 wt %, as depicted in Figure S3b, and mass loss before 100 °C and increase after 600 °C owing to water evaporation and metal ion oxidation, respectively . The carbon properties of the five produced materials were studied by using Raman spectroscopy, as apparent in Figure S3c.…”

NASICON-Type Na3V1.5Cr0.4Fe0.1(PO4)3: High-Voltage and High-Rate Cathode Materials for Sodium-Ion Batteries

“…The growing concerns related to adverse climatic changes and associated remedies in the form of renewable energy have resulted in an increasing need for new energy storage technologies. , The use of high-energy density lithium-ion batteries (LIBs) in long-range electric vehicles is almost inevitable; , however, consumer utilities and demands on secondary batteries as a storage hub for wind and solar energy confirm that sodium-ion batteries (SIBs) are a promising alternative for large-scale energy storage applications owing to the abundance and cost efficiency of sodium resources. , Cathode material development is challenging for SIBs because of the larger size and high charge density of sodium ions, which limit their mobility and diffusion kinetics. , The global material chemist’s attention toward SIBs introduced diverse cathode materials comprising, Prussian blue analogs, polyanionic compounds, and layered oxides. − Among these cathodes, polyanionic compounds are characterized as stable cathode materials because of their superior cycling stability and low-voltage polarization favorable for large-scale energy storage applications …”