Enhanced Polysulfide Regulation via Porous Catalytic V2O3/V8C7 Heterostructures Derived from Metal-Organic Frameworks towards High-Performance Li-S Batteries.
Enhanced Polysulfide Regulation via Porous Catalytic V2O3/V8C7 Heterostructures Derived from Metal-Organic Frameworks towards High-Performance Li-S Batteries.
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DOI：
10.1021/acsnano.0c02762
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发表时间：
2020-06
期刊：
影响因子：
17.1
通讯作者：
Long Zhang;Yicheng Liu;Zedong Zhao;Peilu Jiang;Teng Zhang;Mengxiong Li;Shaoxue Pan;Tianyu Tang-Tianyu-T
中科院分区：
文献类型：
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作者：
Long Zhang;Yicheng Liu;Zedong Zhao;Peilu Jiang;Teng Zhang;Mengxiong Li;Shaoxue Pan;Tianyu Tang-Tianyu-T
锂多硫化物(LiPS)复杂的穿梭效应和缓慢的反应动力学在很大程度上阻碍了锂-S电池的发展。此外，硫的低质量负载量/利用率是导致锂S电池难以商业化的另一个关键因素。本文报道了一种由MIL-47(V)衍生的具有异质结构的多孔催化V_2O_3/V_8C_7@碳复合材料是锂-S电池中有效的多硫化物调节剂，在显著提高硫负载量的同时，仍然有效地抑制了穿梭效应，提高了动力学。系统的机理分析表明，强吸附在V_2O_3表面的LiPS可以通过内建界面快速转移到V_8C_7表面，通过高效的催化作用进行可逆转化，实现了LiPS从捕获到转化的强化调控。此外，多孔结构提供了足够的硫存储空间，使异质结构在高硫负载量的情况下能够充分发挥作用。因此，这种S-V_2O_3/V_8C_7@碳@石墨烯正极具有出色的倍率性能(5℃时为587.6 mAHg~(-1))和长寿命(1000次循环，每次循环0.017%的衰减率)。即使硫负载量为8.1 mg cm-2，它仍然可以提供优越的电化学性能。这些异质结构可以进一步应用于袋细胞，并在不同的折叠角(0-180°)下产生稳定的输出。更关键的是，即使在150次循环后，电池仍可保持4.3mAhcm-2，这高于商用锂离子电池(LIB)的水平。这一解决高硫负载下穿梭效应的策略为高性能锂S电池的进一步发展提供了一种有前途的解决方案。
The development of Li-S batteries is largely impeded by the complicated shuttle effect of lithium polysulfides (LiPSs) and sluggish reaction kinetics. In addition, the low mass loading/utilization of sulfur is another key factor that makes Li-S batteries difficult to commercialize. Here, a porous catalytic V2O3/V8C7@carbon composite derived from MIL-47 (V) featuring heterostructures is reported to be an efficient polysulfide regulator in Li-S batteries, achieving a substantial increase in sulfur loading while still effectively suppressing the shuttle effect and enhancing kinetics. Systematic mechanism analyses suggest that the LiPSs strongly adsorbed on the V2O3 surface can be rapidly transferred to the V8C7 surface through the built-in interface for subsequent reversible conversion by an efficient catalytic effect, realizing enhanced regulation of LiPSs from capture to conversion. In addition, the porous structure provides sufficient sulfur storage space, enabling the heterostructures to exert full efficacy with a high sulfur loading. Thus, this S-V2O3/V8C7@carbon@graphene cathode exhibits prominent rate performance (587.6 mAh g-1 at 5 C) and a long lifespan (1000 cycles, 0.017% decay per cycle). It can still deliver superior electrochemical performance even with a sulfur loading of 8.1 mg cm-2. These heterostructures can be further applied in pouch cells and produce stable output at different folding angles (0-180°). More crucially, the cells could retain 4.3 mAh cm-2 even after 150 cycles, which is higher than that of commercial lithium-ion batteries (LIBs). This strategy for solving the shuttle effect under high sulfur loading provides a promising solution for the further development of high-performance Li-S batteries.