Revealing the Rapid Electrocatalytic Behavior of Ultrafine Amorphous Defective Nb<sub>2</sub>O<sub>5-<i>x</i></sub> Nanocluster toward Superior Li-S Performance.
basic_science · Level V
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- Record sourced from PubMed, PMID 32182038.
- Also identified by DOI 10.1021/acsnano.0c00799.
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Abstract
The notorious shuttling behaviors and sluggish conversion kinetics of the intermediate lithium polysulfides (LPS) are hindering the practical application of lithium sulfur (Li-S) batteries. Herein, an ultrafine, amorphous, and oxygen-deficient niobium pentoxide nanocluster embedded in microporous carbon nanospheres (A-Nb<sub>2</sub>O<sub>5-<i>x</i></sub>@MCS) was developed as a multifunctional sulfur immobilizer and promoter toward superior shuttle inhibition and conversion catalyzation of LPS. The A-Nb<sub>2</sub>O<sub>5-<i>x</i></sub> nanocluster implanted framework uniformizes sulfur distribution, exposes vast active interfaces, and offers a reduced ion/electron transportation pathway for expedited redox reaction. Moreover, the low crystallinity feature of A-Nb<sub>2</sub>O<sub>5-<i>x</i></sub> manipulates the LPS chemical affinity, while the defect chemistry enhances the intrinsic conductivity and catalytic activity for rapid electrochemical conversions. Attributed to these superiorities, A-Nb<sub>2</sub>O<sub>5-<i>x</i></sub>@MCS delivers good Li-S battery performances, that is, high areal capacity of 6.62 mAh cm<sup>-2</sup> under high sulfur loading and low electrolyte/sulfur ratio, superb rate capability, and cyclability over 1200 cycles with an ultralow capacity fading rate of 0.024% per cycle. This work provides a synergistic regulation on crystallinity and oxygen deficiency toward rapid and durable sulfur electrochemistry, holding a great promise in developing practically viable Li-S batteries and enlightening material engineering in related energy storage and conversion areas.