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Electrocatalytic and Conductive Vanadium Oxide on Carbonized Bacterial Cellulose Aerogel for the Sulfur Cathode in Li-S Batteries
oleh: Xueyan Lin, Wenyue Li, Xuan Pan, Shu Wang, Zhaoyang Fan
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2022-12-01 |
Deskripsi
Many transition-metal-oxide-based catalysts have been investigated to chemically bind soluble lithium polysulfides and accelerate their redox kinetics in lithium-sulfur (Li-S) battery chemistry. However, the intrinsic poor electrical conductivities of these oxides restrict their catalytic performance, consequently limiting the sulfur utilization and the rate performance of Li-S batteries. Herein, we report a freestanding electrocatalytic sulfur host consisting of hydrogen-treated VO<sub>2</sub> nanoparticles (H-VO<sub>2</sub>) anchored on nitrogen-doped carbonized bacterial cellulose aerogels (N-CBC). The hydrogen treatment enables the formation and stabilization of the rutile VO<sub>2</sub>(R) phase with metallic conductivity at room temperature, significantly enhancing its catalytic capability compared to the as-synthesized insulative VO<sub>2</sub>(M) phase. Several measurements characterize the electrocatalytic performance of this unique H-VO<sub>2</sub>@N-CBC structure. In particular, the two kinetic barriers between S<sub>8</sub>, polysulfides, and Li<sub>2</sub>S are largely reduced by 28.2 and 43.3 kJ/mol, respectively. Accordingly, the Li-S battery performance, in terms of sulfur utilization and charge/discharge rate, is greatly improved. This work suggests an effective strategy to develop conductive catalysts based on a typical transition metal oxide (VO<sub>2</sub>) for Li-S batteries.