Co-modulating mechanism for Li and Na storage and hydrogen evolution in Co-MoS2/graphene composites
This project aims to investigate the effect of Co-doping on Li/Na-ion storage behaviours in MoS2/graphene composite and its hydrogen generation mechanism. MoS2/graphene composite equips with the high capacity and excellent mechanical stability, which makes it a promising electrode material for both Li-ion and Na-ion batteries. Recent experiments showed that metal doping (e.g., Fe, Ni and Co) can optimize the electrochemical performance of MoS2/graphene composite, in which Co-doping enhances the capacity and cycling stability of MoS2/graphene hybrid and improves its hydrogen generation capability. However, the microscale mechanism is unclear. This project is designed to fully reveal the effect of Co doping on structural, mechanical and electronic properties as well as electrochemical performance (e.g., Li and Na adsorption energy and diffusion kinetics) of MoS2/Gr composites and hydrogen generation performance. It is expected that the outcomes will provide a comprehensive understanding of Li/Na storage mechanism in Co-doped MoS2/Gr composites and a guidance on optimizing MoS2/Gr electrode in Li/Na-ion batteries
Area of science
Energy Materials
Systems used
Magnus
Applications used
1.0MThe Challenge
Despite the excellent electrochemical performance of MoS2/Gr composite, it still suffers from a large structural change during Li/Na intercalation, which gives rise to its quick capacity decay. Although recent researches show that Co-doping could largely improve its capacity and cycling stability, micro-mechanism has not been revealed. Thus, this project is designed to simulate the Li/Na storage behaviour in Co-doped MoS2/Gr composites by using first-principles calculations.
The Solution
First, we compared the structural, electronic and mechanical properties of MoS2/Gr electrode materials before and after Co-doping. Next, Li/Na adsorption in hybrids was simulated and the stable Li/Na adsorption sites were identified. Here, the Li/Na intercalation process was unveiled. Then, we further studied Li/Na kinetic diffusion in hybrids, including diffusion paths and energy barriers. The theoretical capacity and Li/Na intercalation voltage in Co-doped MoS2/Gr hybrid were systematically investigated. Finally, through comparing Li/Na storage behaviours before and after Co-doping, the optimization mechanism of Co-doping was revealed.
The Outcome
The main difficulties for this project are the huge computational tasks because the studies on Li/Na adsorption and kinetic diffusion in hybrid involve a large number of simulations. The Pawsey Centre’s resources enable us to obtain the simulation results in a short time and ensure the smooth progress of simulations. Here, we would like to take this opportunity to thank the Pawsey Centre’s staff for their kind help and support.
List of Publications
[1] Panpan Zhang, Yangyang Yang, Xiaoguang Duan, Shu Zhao, Chunsheng Lu, Yonglong Shen, Guosheng Shao, Shaobin Wang. Mechanistic investigations of N-doped graphene/2H(1T)-MoS2 for Li/K-ions batteries, Nano Energy, 2020, 78, 105352.
[2] Chao Yang, Fan Lv, Kang Dong, Feili Lai, Kangning Zhao, Fu Sun, Shuming Dou, Qian Wang, Jie Xu, Panpan Zhang, Tobias Arlt, Xiaodong Chen, Ingo Manke, Shaojun Guo. Carbon-coated ultrathin metallic V5Se8 nanosheet achieves high-energy-density and robust potassium storage, Energy Storage Materials, 2020, 35, 1‒11.
[3] P.P. Zhang, Y.Y. Yang, X.G. Duan, C. Lu, S.B. Wang, Atomic exploration of Co-doped MoS2/graphene hybrids as high-rate and long-life anode material for Li/Na ions batteries, ACS Applied Materials & Interfaces, in preparation.
Figure 1. The structures of MoS2/Gr with Co-doping at different sites.
Figure 2. The density of states of Co-doped MoS2/Gr composite with Co atom located at different sites
