Na${}_4$Co${}_3$(PO${}_4$)${}_2$P${}_2$O${}_7$/NC composite as a negative electrode for sodium-ion batteries

Abstract

In recent years, the mixed phosphates based polyanionic electrode materials have attracted great attention in sodium-ion batteries due to their structural stability during cycling and open framework for ion diffusion. Here, we report the electrochemical performance of Na${}_4$Co${}_3$(PO${}_4$)${}_2$P${}_2$O${}_7$/nitrogen doped carbon (NCPP/NC) composite as a negative electrode (anode) for sodium ion batteries in the working potential range of 0.01--3.0~V. It delivers a reversible discharge capacity of 250~mAhg${}^{-1}$ at 0.5~C current rate, which corresponds to the insertion/extraction of four sodium ions. The rate capability study indicates the reversible mechanism and highly stable capacity (61 mAhg${}^{-1}$) even at high rate up to 5~C as compared to pristine NCPP. The incorporation of the N doped carbon spheres in the composite is expected to enhance the electronic/ionic conductivity, which plays an important role in improving the performance and stability up to 400 cycles at 1~C rate. Intriguingly, the analysis of cyclic voltammetry data measured at different scan rates confirm the capacitive/diffusive controlled mechanism and the extracted diffusion coefficient is found to be around 10${}^{-10}$ cm${}^2$s${}^{-1}$. Our results demonstrate that the NCPP/NC composite is also a potential candidate as anode in sodium-ion batteries due to its three dimensional framework, cost effectiveness, enhanced specific capacity as well as further possibility of improving the stability.

ACS Applied Energy Materials (2021)

References in corpus (2)

• Chemically active substitutional nitrogen impurity in carbon nanotubes
• Electrochemical properties of Na${}_{0.66}$V${}_4$O${}_{10}$ nanostructures as cathode material in rechargeable batteries for energy storage applications