Nano Sn4P3 embedded in nitrogenous carbon matrix as the anode of sodium ion battery for enhanced cyclability

Abstract

Sodium ion batteries (SiBs) is a promising candidate to substitute the lithium ion batteries (LiBs) considering the geopolitical abundance of Na sources in the earth. Nevertheless, the preparation of an anode with satisfactory energy density is generally complicated with limited efficiency, causing a tough challenge to the wide application of SiBs to date. Herein, a highly efficient three-step approach of in-situ synthesizing and embedding nano Sn4P3 within the nitrogenous carbon matrix to construct Sn4P3/CN composite was developed. The nano Sn4P3 particles with a diameter less than 50 nm were successfully formed and separated by nitrogenous carbon matrix, in which Sn4P3 could act as the core material with high capacity while the carbon matrix could act as the electron expressway and mechanical supporter. As a result, superior capacity performance can be achieved for the SiBs using the Sn4P3/CN as the anode, which maintained 476.6 mA h g−1 at 60th cycle under 0.1 A g−1, and ~430, ~310, ~245, ~190 mA h g−1 can be obtained at 1, 1.5, 2, and 3 A g−1, respectively. In short, the in-situ construction of Sn4P3/CN with well-controllable morphology was developed, demonstrating preferable application as anode material of SiBs, and thus providing a cost-efficient strategy for scalable preparation of high-performance Sn4P3 anode and other metal phosphide materials.