Ti 2 P monolayer as a high performance 2-D electrode material for ion batteries

• Published in: Physical chemistry chemical physics : PCCP 2020-09, Vol.22 (33), p.18480-18487
• Main Authors: Cheng, Zishuang, Zhang, Xiaoming, Zhang, Hui, Liu, Heyan, Yu, Xiao, Dai, Xuefang, Liu, Guodong, Chen, Guifeng
• Format: Article
• Language: English
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/D0CP02874F

Electrical conductivity, storage capacity and ion diffusion ability are three crucial parameters for battery electrode materials. However, rare existing two-dimensional (2-D) electrode materials can achieve high performances in all these parameters. Here, we report that a 2-D transition-metal phosphide, the Ti 2 P monolayer, is a promising superior electrode material which realizes high performances in all the parameters mentioned above. The Ti 2 P monolayer has a stable honeycomb crystal structure. It has a metallic electronic structure with Li/Na adsorption, which ensures good electrical conductivity during the battery operation. We find that Li/Na can chemically bond to the Ti 2 P substrate, with specific charge exchanges. Our results show the Li/Na capacity in the Ti 2 P monolayer is about 846 mA h g −1 , which is much higher than that of the graphite anode. Remarkably, the Li/Na diffusion barrier on the Ti 2 P monolayer is only 12–16 meV, which is lower than that in all 2-D anode materials proposed till now. Our work highly promises that theTi 2 P monolayer can serve as a superior anode material for Li-ion/Na-ion batteries by providing good electrical conductivity, high storage capacity and ultrafast ion diffusion.