期刊
CHEMICAL ENGINEERING JOURNAL
卷 475, 期 -, 页码 -出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.cej.2023.146180
关键词
First principles calculations; Haploid CuP 2 cluster; Reaction mechanism; Diffusion energy barrier; Anchoring effect; Single vacancy graphene
CuP2 is a hopeful anode material for sodium-ion batteries with considerable theoretical capacity. However, it suffers from rapid capacity decline and cyclic reversibility issues. Single vacancy graphene (SVG) plays a key role in regulating the electrochemical properties of CuP2, leading to more stable reaction energy barrier and higher theoretical capacity of CuP2/SVG composites.
CuP2 is considered as a promising anode material for sodium-ion batteries due to its considerable theoretical capacity (1280 mAh/g), but it suffers from rapid decline of capacity and its cyclic reversibility should be further improved. As far as possible, preventing reaction energy barrier from sudden change and holding back Cu diffusion at atomic level both are key strategies to solve these problems occurring on the electrochemical reaction between CuP2 and Na. Based on the surface anchoring effect and excellent electronic conductivity of single vacancy graphene (SVG), first principles calculations have been carried out to capture the key role of SVG in regulating the electrochemical properties of CuP2. Firstly, among various (CuP2)n (n = 1-6) clusters, haploid CuP2 cluster possesses the fairly stable structure due to its highest HOMO-LUMO gap (2.45 eV) and lowest vertical electronic affinity energy (0.64 eV). Most of all, CuP2/SVG composites exhibit much more stable reaction energy barrier than CuP2 during their Na storage. It is attributed to the strong C-P and Cu-C anchoring effect between CuP2 and SVG, slowing the break of Cu-P bond. This contributes to holding back volume mutations of CuP2/SVG during Na storage. Besides, after conversion reaction between CuP2/SVG and Na, Cu showsdiffusion energy barrier of 0.75 eV, exhibiting great difficulty for its migration in reaction products. Compared with CuP2, CuP2/SVG not only exhibits more stable voltage distribution, but also it has much higher theoretical capacity (1851 mAh/g vs.1280 mAh/g). That is to say. CuP2/SVG can be acted as anode materials for Na-ion batteries with high energy density. And our results also provide a new way to design long-life CuP2-based anode materials for Na-ion batteries.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据