Doping engineering in MoS₂ as the cathode-host in lithium‑sulfur batteries

A first principles investigation

authored by

Maryam Abbasi, Irmgard Frank, Ebrahim Nadimi

Abstract

The practical application of lithium‑sulfur batteries is hindered by the dissolution of lithium polysulfides, causing a reduction in coulombic efficiency and cyclic performance, known as the shuttle effect. Addressing this requires identifying suitable anchoring materials. Metal sulfides, particularly two-dimensional structures like MoS₂, emerge as promising candidates for anchoring cathode hosts in lithium‑sulfur batteries. Their attributes include sufficient adsorption energy toward polysulfides and commendable catalytic activity compared to carbon electrodes. However, their limited electrical conductivity poses a significant obstacle to efficient electron flow. In this study, employing density functional theory (DFT), we elucidate strategies for enhancing the electrical conductivity and anchoring capabilities of the basal plane of MoS₂ by introducing impurities at S and Mo sites. Our investigation encompasses a range of metal dopants, including V, Ni, Co, Mn, and Fe, and non-metal atoms such as Se and P in combination with vacancies. Through meticulous examination of formation energies and induced electrical conductivity, certain dopants, both in isolation and co-doping configurations, have been identified for further scrutiny. Our findings reveal that P and V dopants exhibit low formation energies within the MoS₂ structure while they improve the electrical conductivity compared to other dopants. Additionally, they demonstrate superior adsorption energies required to immobilize lithium polysulfide species effectively. Notably, the synergistic effects observed in co-doped PV-MoS₂ samples markedly enhance the binding energy of Li₂S_n species on the MoS₂ monolayer which is supported by the ICHOP values. This dual-doping approach also facilitates the conversion of polysulfides to final products and has the low energy barrier of Li₂S decomposition that accelerates the kinetics of lithium‑sulfur batteries during the charge and discharge process. Overall, our research provides valuable insights into optimizing the electrical and anchoring properties of MoS₂ for enhanced performance in lithium‑sulfur batteries.

Organisation(s)

Institute of Physical Chemistry and Electrochemistry

External Organisation(s)

K.N. Toosi University of Technology

Type

Article

Journal

Journal of Energy Storage

Volume

95

No. of pages

11

Publication date

01.08.2024

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Electrical and Electronic Engineering

Sustainable Development Goals

SDG 7 - Affordable and Clean Energy

Electronic version(s)

https://doi.org/10.1016/j.est.2024.112555 (Access: Closed)