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Vanadium based carbide-oxide heterogeneous V2O5@V2C nanotube arrays for high-rate and long-life lithium-sulfur batteries.
Nanoscale ( IF 5.8 ) Pub Date : 2020-08-18 , DOI: 10.1039/d0nr05199c
Zhenguo Wang 1 , Ke Yu , Shijing Gong , Erwei Du , Ziqiang Zhu
Affiliation  

Due to their ultra-high theoretical energy density, low cost, and environmental friendliness, lithium–sulfur batteries have become a potentially strong competitor for next-generation energy storage devices. The search for a host material that can effectively anchor sulfur to a cathode to solve the adverse effects of the shuttle effect on batteries has become a research hotspot in the academic world. Here, we propose a three-dimensional heterostructure of V2O5 nanotube arrays vertically grown on V2C-MXenes as a sulfur-supporting host material for the cathode of lithium–sulfur batteries. Through first-principles calculations, we found that V2O5@V2C exhibits an extreme adsorption capacity for polysulfides. Besides, thanks to the excellent catalytic performance of V2O5 for oxidation reactions, the conversion reaction potential of polysulfides to Li2S and Li2S2 is significantly reduced, and the shuttle effect of lithium–sulfur batteries is effectively suppressed. Also, the larger specific surface area and tubular structure of the composite host material can increase the sulfur loading of the cathode while ensuring the stability of the electrode structure. The V2O5@V2C/S electrode exhibits higher initial capacity (1173 mA h g−1 at 0.2C), longer cycle life (1000 cycles with 0.047% decay per period), and higher sulfur loading (8.4 mg cm−2). We believe that this work can provide a reference for the design of cathode host materials for lithium–sulfur batteries with long cycle life.

中文翻译:

钒基碳化物-氧化物异质V2O5 @ V2C纳米管阵列,用于高速率和长寿命的锂硫电池。

由于其极高的理论能量密度,低成本和环境友好性,锂硫电池已成为下一代储能设备的强大竞争对手。寻找能够有效地将硫锚定到阴极上以解决穿梭效应对电池的不利影响的基质材料已成为学术界的研究热点。在这里,我们提出了在V 2 C-MXenes上垂直生长的V 2 O 5纳米管阵列的三维异质结构,作为锂硫电池阴极的硫支撑基质材料。通过第一性原理计算,我们发现V 2 O 5 @V 2C对多硫化物具有极强的吸附能力。此外,由于V 2 O 5对氧化反应的出色催化性能,大大降低了多硫化物向Li 2 S和Li 2 S 2的转化反应电位,并有效地抑制了锂硫电池的穿梭效应。而且,复合主体材料的较大的比表面积和管状结构可以增加阴极的硫负荷,同时确保电极结构的稳定性。V 2 O 5 @V 2 C / S电极具有更高的初始容量(1173 mA hg -1在0.2C下),更长的循环寿命(1000次循环,每周期衰减0.047%)和更高的硫负载量(8.4mg cm -2)。我们相信,这项工作可以为设计周期长的锂硫电池正极主体材料提供参考。
更新日期:2020-09-24
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