Dual-element-doped graphene/2H(1T)-MoS2 composites as anode materials for K-ion battery

This project aims to investigate the effect of dual elements-doping on the K-ion storage behaviours in graphene/2H-MoS2 and graphene/1T-MoS2 composites (Gr/2H(1T)-MoS2). N-doped Gr/2H(1T)-MoS2 composites equip with the high capacity and excellent mechanical stability, which makes it a promising electrode material for K-ion batteries. However, K ions adsorption on N-doped Gr is relatively weak, which affects the effective storage of K ions. Recent experimental studies revealed that dual doping of N and another element (such as S, O or B) in graphene/hard carbon could increase K adsorption and enhance its structural stability during electrochemical cycles. Thus, we aim to introduce the dual elements-doping in Gr/2H(1T)-MoS2 to further optimize the electrochemical performance. This project is designed to fully reveal the effect of dual elements-doping on the structure, mechanical, electronic properties and electrochemical performance (such as K adsorption energy and diffusion kinetics) of Gr/2H(1T)-MoS2 composites. It is expected that the outcomes will provide a comprehensive understanding of the K storage mechanism in dual elements-doped Gr/2H(1T)-MoS2 composites.

Principal investigator

Chunsheng Lu c.lu@curtin.edu.au
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Area of science

Energy Materials

Systems used


Applications used

Partner Institution: Curtin University| Project Code: pawsey0371

The Challenge

Despite the excellent electrochemical performance of MoS2/Gr composite, it still suffers from large structural change during K intercalation, which gives rise to its quick capacity decay. Although recent research showed that dual elements-doping could largely improve its capacity and cycling stability, the micro-mechanism cannot be revealed from experiments. Thus, this project is designed to simulate the K storage behaviour in dual elements-doped Gr/2H(1T)-MoS2 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 dual elements-doping. Here, we chose N and S, N and O, and N and B to study the effects of dual-elements-doping. Next, K adsorption in hybrids was simulated, and the stable K adsorption sites were identified. Here, the K intercalation process was also unveiled. Then, we further studied K kinetic diffusion in hybrids, including diffusion paths and energy barriers. The theoretical capacity and K intercalation voltage in dual elements-doped Gr/2H(1T)-MoS2 hybrids were systematically investigated. Finally, through comparing K storage behaviours before and after doping, the optimization mechanism of dual elements-doping can be revealed.

The Outcome

The main difficulty of this project is the huge computational tasks since studies on K adsorption and kinetic diffusion in three dual-elements-doped Gr/2H(1T)-MoS2 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.

Figure 1. The interface binding strength (W_sep) of dual-elements-doped Gr/1T-MoS2 with four different configurations, with W_sep of NGr/1T-MoS2 for comparison.
Figure 2. The most stable structures of (a) NGr/1T-MoS2, (b) N, O-doped Gr/1T-MoS2, (c) N, S-doped Gr/1T-MoS2 and (d) N, B-doped Gr/1T-MoS2 hybrids.