Progress has been made in the research of MoS2 lithium ion battery electrode materials

[ Instrument Network Instrument R & D ] Recently, the research group of Zhao Bangchuan, a researcher in the functional materials laboratory of the Institute of Solid State Research, Chinese Academy of Sciences, has made a series of progress in the research of MoS2 lithium ion batteries (LIBs) electrode materials. The relevant research results were published on ChemElectroChem, Nanoscale, Small .

Cycle and rate performance of MoS2 / Co composites

Rechargeable lithium-ion batteries have important applications in electric vehicles, portable electronic products, energy storage grids and other fields and have received widespread attention. However, due to the low theoretical specific capacity (372 mAh / g) of current commercial graphite anode materials, they cannot meet people's requirements for battery energy and power density, and their rate performance is poor. Chemical properties. In addition, the extremely low working voltage of graphite makes LIBs have a greater safety hazard when working. Therefore, the exploration of anode materials with high safety, high specific capacity, high rate performance, and high cycle performance is a hot topic in the current research field of LIBs.

V4C3-MXene / MoS2 / C composite material structure diagram and rate performance

Compared with graphite, materials with two-dimensional / quasi-two-dimensional crystal structures can be applied to lithium due to their relatively safe operating voltage, large specific surface area, rich active sites, and fast ion / electron transfer capabilities. Ion battery negative material. As a typical representative of two-dimensional materials, MoS2 has a graphene-like layered structure and high theoretical specific capacity (669 mAh / g). However, when MoS2 is used as a negative electrode material of LIBs, there are disadvantages such as poor rate performance due to poor material conductivity, and poor stability due to large volume changes during cycling. In order to solve the above problems, the research group carried out modification research on MoS2 electrode materials, and obtained MoS2 electrode materials with superior electrochemical performance.

Synthetic process, reaction mechanism and rate performance of 1T-MoS2 / C composites

In response to the problem of poor conductivity of the MoS2 electrode material, the use of a higher conductivity metal Co simple substance and MoS2 composite effectively improved the material's electrical conductivity and the electrochemical performance of the material. At a current density of 2 A / g, its capacity can still be maintained above 700 mAh / g. The related results were published on ChemElectroChem.

In order to further improve the cycle stability of the electrode, V4C3MXene (Mecene) and MoS2 were used for compounding, and a carbon coating process was used to prepare a V4C3-MXene / MoS2 / C composite material. Since V4C3-MXene can effectively enhance the conductivity of the material And electrode structure stability, carbon coating can further stabilize the structure of the material and increase the specific surface area of ​​the material, thereby significantly improving the electrochemical performance of the electrode material, V4C3-MXene / MoS2 / C electrode at 1 A / g current density After 450 cycles, its capacity can reach about 600 mAh / g. Even at a current density of 10 A / g, the capacity can still be maintained at about 500 mAh / g. Related results were published on Nanoscale. Compared with the above 2H phase MoS2, the 1T phase MoS2 has advantages in conductivity and interlayer distance. However, the current preparation process of the 1T phase MoS2 is complicated, and the 1T phase MoS2 obtained is also unstable.

We used glucose-assisted hydrothermal method to synthesize 1T-MoS2 and carbon composite 1T-MoS2 / C material with a small layer structure. The MoS2 composite has an initial specific capacity of 920.6 mAh / g at a current density of 1A / g. The secondary cycle capacity is 870mAh / g, and the specific capacity can still be maintained at about 600 mAh / at a large current density of 10A / g, which shows excellent cycle and rate performance. Related results were published on Small.

The above work was supported by the National Key Research and Development Program and the National Science Foundation of China Science Device Joint Fund Project.