Electrocatalytic and Conductive Vanadium Oxide on Carbonized Bacterial Cellulose Aerogel for the Sulfur Cathode in Li-S Batteries
Electrocatalytic and Conductive Vanadium Oxide on Carbonized Bacterial Cellulose Aerogel for the Sulfur Cathode in Li-S Batteries
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DOI：
10.3390/batteries9010014
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发表时间：
2022-12
期刊：
影响因子：
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通讯作者：
Xueyan Lin;Wenyue Li;X. Pan;Shu Wang;Z. Fan
中科院分区：
文献类型：
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作者：
Xueyan Lin;Wenyue Li;X. Pan;Shu Wang;Z. Fan
人们已经研究了许多基于过渡金属氧化物的催化剂，以化学方式结合可溶性多硫化锂并加速其在锂硫（Li-S）电池化学中的氧化还原动力学。然而，这些氧化物固有的较差的导电性限制了它们的催化性能，从而限制了硫的利用率和锂硫电池的倍率性能。在此，我们报道了一种独立的电催化硫主体，由锚定在氮掺杂碳化细菌纤维素气凝胶（N-CBC）上的经氢处理的 VO2 纳米颗粒（H-VO2）组成。氢处理能够在室温下形成并稳定具有金属导电性的金红石VO2(R)相，与合成的绝缘VO2(M)相相比，显着增强其催化能力。多项测量表征了这种独特的 H-VO2@N-CBC 结构的电催化性能。特别是，S8、多硫化物和Li2S之间的两个动力学势垒分别大大降低了28.2和43.3 kJ/mol。因此，锂硫电池的硫利用率和充放电倍率方面的性能大大提高。这项工作提出了一种开发基于典型过渡金属氧化物（VO2）的锂硫电池导电催化剂的有效策略。
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 VO2 nanoparticles (H-VO2) anchored on nitrogen-doped carbonized bacterial cellulose aerogels (N-CBC). The hydrogen treatment enables the formation and stabilization of the rutile VO2(R) phase with metallic conductivity at room temperature, significantly enhancing its catalytic capability compared to the as-synthesized insulative VO2(M) phase. Several measurements characterize the electrocatalytic performance of this unique H-VO2@N-CBC structure. In particular, the two kinetic barriers between S8, polysulfides, and Li2S 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 (VO2) for Li-S batteries.