Lithium-sulfur battery performance will be greatly improved!

Lithium-sulfur batteries have the characteristics of large theoretical capacity and high energy density, as well as a wide range of sulfur sources and environmentally friendly materials. They are expected to become the next generation of high-performance lithium-ion batteries. However, there are still many technical challenges in its commercial application, such as poor conductivity of solid sulfides, shuttle effect of soluble polysulfide intermediates, and large volume changes during charge and discharge processes.

At present, researchers have explored a variety of ways to solve the above problems:

(1) Enhancing conductivity and suppressing diffusion of polysulfide by electrode structure design;

(2) Suppressing the shuttle effect by adjusting the electrolyte composition, the separator structure, and the binder component;

(3) Protection on the surface of the metal lithium negative electrode to prevent side reactions of polysulfide and lithium.

Despite this, the irreversible loss of the active substance has not been completely solved. Recently, Guo Shaojun, a researcher at Peking University and postdoctoral Zhang Yelong, combined the defect chemistry with lithium-sulfur batteries. For the first time, the concept of “positively charged sulfur vacancies” was introduced in the lithium-sulfur battery system, and the 1T-rich phase MoS2 and the positive charge were synthesized for the first time. The sulfur vacancy MXene/1T-2HMoS2-C hybrid material utilizes a large number of "positively charged sulfur vacancies" to effectively anchor negatively charged polysulfide anions, providing fast electronic conduction paths using 3D MXene and 1TMoS2.

This material exhibits excellent electrochemical properties. At a current rate of 0.1 C, the button lithium-sulfur battery has a specific capacity of 1194.7 mAh/g at a rate of 0.5 C, after 300 cycles, the battery capacity can be maintained at 799.3 mAh/g, with only 0.07% attenuation per revolution, the soft-packed lithium-sulfur battery assembled with this material can achieve a stable cycle of 40 cycles.

This work not only designed 1T/2H phase interface, rich positive electric S vacancies, three-dimensional MXene conductive skeleton, and combined physical adsorption, chemisorption, defect chemistry, and interface catalysis, using MXene/1T-2HMoS2-C The catalytic effect and its limited anchorage effect enable the rapid reversible transformation of polysulfide, which provides an effective method for the design of cathode materials for lithium-sulfur batteries. It provides ideas for the development of high-performance lithium-sulfur batteries and opens up defects in chemistry and lithium. The organic combination of sulfur batteries has guiding significance for the design and practical use of lithium-sulfur batteries.

The page contains the contents of the machine translation.