Direct Studies on the Lithium-Storage Mechanism of Molybdenum Disulfide

Abstract

Transition metal sulfides are regarded as a type of high-performance anode materials for lithium ion batteries (LIBs). However, their electrochemical process and lithium-storage mechanism are complicated and remain controversial. This work is intended to give the direct observation on the electrochemical behavior and find out the lithium-storage mechanism of molybdenum disulfide (MoS2) using in situ transmission electron microscopy (TEM). We find that single-crystalline MoS2 nanosheets convert to Mo nanograins (~2 nm) embedded in Li2S matrix after the first full lithiation. After the delithiation, the Mo nanograins and Li2S transform to a large number of lamellar MoS2 nanocrystals. The discharge-charge cycling of MoS2 in LIBs is found to be a fully reversible conversion between MoS2 and Mo/Li2S rather than the electrochemical conversion between S and Li2S proposed by many researchers. The in situ real-time characterization results give direct evidence and profound insights into the lithium-storage mechanism of MoS2 as anode in LIBs.

Carbon Cloth Decorated with MoS2 Microflowers as Flexible Binder‐Free Anodes for Lithium and Sodium Storage

“…In the second and subsequent cathodic scans, the reduction peaks shift to around 1.0 and 1.8 V, indicating that lithiation mechanisms in the second and the subsequent cycles are different from the first cycle. In the subsequent anodic scans, the oxidation peaks at ≈1.5 and 2.29 V should be related to the oxidation of Mo nanoparticles to the MoS 2 phase . The sharp peak at 0.25 V corresponds to lithium‐ion extraction from CC .…”

How does Molybdenum Disulfide Store Charge: A Minireview

“…The structural evolution of MoS 2 electrodes has been intensively studied by using a number of in/ex situ characterization methods and theoretical calculations . The structural stability of commercial micrometer‐sized MoS 2 cycled in different voltage ranges was studied by Chen and co‐workers (Figure ) .…”

High-throughput first-principles-calculations based estimation of lithium ion storage in monolayer rhenium disulfide

“…However, recent experimental studies have established this to be a real-life phenomenon. Su et al 33 observed in their in situ transmission electron microscopic (TEM) study that single-crystalline MoS 2 nanosheets convert to Mo nanograins with broken Mo-S bonds which helps in forming an Li 2 S matrix for the nanograins after the first full lithiation. After the delithiation, they observed the disappearance of the Li 2 S phase and We define the adsorption energy (E ads ) for the multi-Li adsorbed ReS 2 phases as…”

“…(ii) It is difficult to find single Li binding sites on distorted crystals, which further inhibits the calculation of the diffusion barriers. Furthermore, recent in situ 33 and ex situ 34 measurements demonstrate metal-sulphur bond breaking during lithiation and restoration during delithiation process in TMD anode-based LIBs. None of those earlier studies consider such bond breaking in their firstprinciples based calculations.…”