Three-dimensional carbon nanotube networks enhanced sodium trimesic: a new anode material for sodium ion batteries and Na-storage mechanism revealed by ex situ studies

Xin Yan,Yan-Ping Zheng,Xing-Long Wu,Huan Ye,Mingkai Liu,Xiao-Hua Zhang,Fang Wan,Yu-Guo Guo,Jing-Ping Zhang

doi:10.1039/c7ta03484a

Abstract

A new organic material (Na3TM) is proposed as an advanced anode for SIBs, and its Na-storage mechanism is ascertained.

Highlights

In the past two decades, lithium ion batteries (LIBs) have played a signi cant role in powering diverse electrical equipment, such as portable consumer electronics, electric vehicles, and grid-scale energy storage stations.[1,2,3,4,5] With the rapid development of these areas, the increasing use of LIBs will inevitably lead to the shortage of Li sources, and the continuous price rise of LIBs in the near future.[6,7,8,9] It is becoming more and more urgent to seek appropriate alternatives for LIBs
Because of the microstructure observed, the as-prepared composite was abbreviated as carbon nanotubes (CNTs)-NWs@Na3TM, suggesting that the active Na3TM material has been well implanted into the CNT NWs
Such a speci c structure will be very helpful in improving the Na-storage properties, and in making the asprepared CNT-NWs@Na3TM composite exhibit a much enhanced electrochemical performance compared to the control of pure Na3TM microparticles

Summary

Introduction

For the anode of SIBs, most of the traditional inorganics with superior Li-storage properties[17] do not exhibit the expected Nastorage capacity mainly because of the larger radius of the Na ion compared to that of its Li counterpart.[18]. When used as an anode material for SIBs, the Na3TM could deliver a reversible Nastorage capacity of 214.6 mA h gÀ1 at a low current density of 0.1 A gÀ1, and exhibited excellent rate performance with the speci c capacities of 149 and 87.5 mA h gÀ1 at high current densities of 1 and 10 A gÀ1, respectively. It was interesting to discover that two of the Na uptake/release processes were reversible during cycling to contribute to the Na-storage capacity but the 1st sodiation process with three Na uptake was not

Synthesis

Structural characterizations

Electrochemical measurements

Results and discussion

Conclusions