New progress in lithium-sulfur battery research: a nanoreactor modified by sulfide catalyst

Lithium-sulfur battery is a new type of reversible lithium battery with high energy density and broad application prospects. However, the dissolution of lithium polysulfide compounds and the existence of polysulfide shuttle effects in body electrolyte systems limit their application. In recent years, researchers have solved these problems by developing functional electrolyte additives and constructing new electrode materials to expand the application of lithium-sulfur batteries.

Recently, researchers at the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences have designed a nano-reactor modified with a sulfide catalyst through molecular-level design and applied it to the positive electrode of a lithium-sulfur battery. They have successfully constructed an excellent catalytic activity and cycle stability Sulfur cathode composite material.

The nano reactor is composed of nano particles embedded in multi porous nitrogen doped carbon spheres. The nano reactor has high specific surface area, large pore volume, and can enhance the adsorption and electrical conversion to lithium polysulfide. In addition, the large mesopores generated in situ in the carbon spheres can hold up to 75% of the high sulfur load, maintain volume change during the charge / discharge cycle, and improve ion / mass transfer.

The researchers theoretically predicted and experimentally confirmed the excellent adsorption performance of the nano-reactor for lithium polysulfide. In addition, the researchers also verified the electro-catalytic activity of the nano-reactor, proving its performance as a positive electrode material for lithium-sulfur batteries Excellent, at a current density of 0.5 C, the capacity is maintained at 1070 mA with 200 cycles per gram and almost no attenuation. Moreover, the performance of lithium-sulfur batteries based on the anode material of the nanoreactor is significantly enhanced, and it has a high rate and cycle capacity even under a high sulfur load of 8.14 mg cm^-2.

This nano-reactor has low mass density and high porosity, which significantly improves the ability to adsorb, catalyze and convert polysulfides.It provides new ideas for studying the migration and diffusion of ions in the nanospace and constructing high-capacity, long-cycle metal-sulfur batteries.

references:

Yash Boyjoo, Haodong Shi, Qiong Cai, Jian Liu , Gao Qing (Max) Lu,et al.Molecular‐Level Design of Pyrrhotite Electrocatalyst Decorated Hierarchical Porous Carbon Spheres as Nanoreactors for Lithium–Sulfur Batteries[J].Advanced Energy Materials. https://doi.org/10.1002/aenm.202000651