A Sulfur Cathode Design Strategy for Polysulfide Restrictions and Kinetic Enhancements in Li-S Batteries through Oxidative Chemical Vapor Deposition
A Sulfur Cathode Design Strategy for Polysulfide Restrictions and Kinetic Enhancements in Li-S Batteries through Oxidative Chemical Vapor Deposition
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DOI：
10.1016/j.nanoen.2023.108756
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发表时间：
2023-08
期刊：
影响因子：
17.6
通讯作者：
Yuxuan Zhang;Hancheul Song;K. Crompton;Xixian Yang;K. Zhao;Sunghwan Lee
中科院分区：
文献类型：
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作者：
Yuxuan Zhang;Hancheul Song;K. Crompton;Xixian Yang;K. Zhao;Sunghwan Lee
锂硫（Li-S）电池为实现高密度和低成本的能量存储设备提供了一个有前途的解决方案。然而，多硫化物从阴极到电解液和阳极的传输是阻碍锂硫电池实际利用的主要瓶颈，这导致电解液的有害降解和阳极上微观结构的不均匀演变，最终导致容量快速衰减。为了克服这一限制，我们提出了一种突破性的缓解策略，利用氧化化学气相沉积（oCVD）技术来限制阴极中多硫化物的穿梭。这种气相方法的独特之处在于，高导电性和保形聚合物涂层完全消除了阴极中传统粘合剂的使用，同时增强了硫转化的动力学条件，抑制了电池运行过程中多硫化物的穿梭。互补的实验和理论研究表明，多硫化物在物理和化学上被限制在阴极区域。使用这种方法制造的硫阴极具有高活性物质负载（90 wt%），高硫利用率为84.4% (0.1 C时~ 1413 mAh g−1)，在0.5 C下300次循环后（~ 810 mAh g−1）的容量保持率为85%。袋状电池还具有高达202 Wh kg−1的高比能，低电解质/硫比为4.55，证明了实际应用的巨大潜力。
Lithium-sulfur (Li-S) batteries offer a promising solution for achieving high-density and low-cost energy storage devices. However, the practical utilization of Li-S batteries is hindered by the main bottleneck of polysulfides transport from the cathode to the electrolyte and anode, which leads to the detrimental degradation of the electrolyte and non-uniform microstructure evolution on the anode, ultimately resulting in rapid capacity fading. To overcome this limitation, we propose a groundbreaking mitigation strategy that leverages the oxidative chemical vapor deposition (oCVD) technique to limit the shuttling of polysulfides in the cathode. This gas-phase approach is unique in that highly conducting and conformal polymer coating entirely eliminates the use of traditional binders in the cathode while enhancing the kinetic conditions of the sulfur conversion and inhibiting the shuttling of polysulfides during battery operation. Complementary experimental and theoretical investigations identify that polysulfides are physically and chemically confined in the cathode region. The sulfur cathode manufactured using this approach demonstrates high active material loading (90 wt%), a high sulfur utilization ratio of 84.4% (∼1413 mAh g−1at 0.1 C), and capacity retention of 85% after 300 cycles (∼810 mAh g−1) at 0.5 C. The pouch cell also showcases a high specific energy of up to 202 Wh kg−1with a low electrolyte/sulfur ratio of 4.55, proving the immense potential for practical applications.