Na$_{4}$Co$_{3}$(PO$_{4}$)$_{2}$P$_{2}$O$_{7}$/NC composite as a negative electrode for sodium-ion batteries

Pravin K. Dwivedi; Simranjot K. Sapra; Jayashree Pati; Rajendra S. Dhaka

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arXiv · 2107.09524

Na$_{4}$Co$_{3}$(PO$_{4}$)$_{2}$P$_{2}$O$_{7}$/NC composite as a negative electrode for sodium-ion batteries

Pravin K. Dwivedi·Simranjot K. Sapra·Jayashree Pati·Rajendra S. Dhaka

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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.

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Pravin K. Dwivedi, Simranjot K. Sapra, Jayashree Pati, Rajendra S. Dhaka. 2021-07-20. Na$_{4}$Co$_{3}$(PO$_{4}$)$_{2}$P$_{2}$O$_{7}$/NC composite as a negative electrode for sodium-ion batteries. https://arxiv.org/abs/2107.09524

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