Surface High-Performance Matrix Boosts Li-S Battery Performance

The design and optimization of the surface electrochemical active sites is hot research for catalysts and batteries. Lithium-sulfur batteries provide a high energy density while being low cost and environmentally friendly. Challenges still exist. Researchers in China and Canada proposed an atomic terminated concept to design the facet via single-crystal architecture for Li-S batteries. The concept harvests high-density/efficient surface active sites where the chemical reaction takes place to boost the electrocatalyst performance of Li-S batteries significantly. They published their findings in Nano Research. Electrochemical catalytic active sites on the surface enhance Li-S batteries’ polysulfide conversion and performance.

The researchers suggest that using a single-crystal architecture can solve some of the challenges. Their study used the atomic high-rich Co³⁺-Se terminated (ACT) concept to create a high-performance matrix. Using a simple hydrothermal process, they synthesized a single-crystal CoSe₂ (scCS) wrapped by reduced graphene oxide. The single-crystal architecture in scCS can suppress the shuttle effect and reduce polarization. This effectively boosts the lithium-ion migration and lowers the barrier of polysulfides.

Given the single-crystal structure of CoSe₂, the facets of scCS can be stacked by the obvious pure Co/Se atoms, in contrast with mixed terminated facets found in polycrystal CoSe₂ samples. With the single-crystal architecture of CoSe₂, the team sees the potential to easily achieve the large atomic density and highly effective surface-active sites. They reached a high efficient surface-active site concentration of more than 69 percent.

In the future, the research team sees potential for their new method and that it might prove useful in areas beyond the Li-S batteries.