Xia Jun, Gao Runhua, Yang Yang, Tao Zheng, Han Zhiyuan, Zhang Shichao, Xing Yalan, Yang Puheng, Lu Xia, Zhou Guangmin
School of Materials Science and Engineering, Beihang University, Beijing100191, PR China.
Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute & Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen518055, PR China.
ACS Nano. 2022 Nov 22;16(11):19133-19144. doi: 10.1021/acsnano.2c08246. Epub 2022 Nov 4.
The development of lithium-sulfur (Li-S) batteries with high-energy density, flexibility, and safety is very appealing for emerging implantable devices, biomonitoring, and roll-up displays. Nevertheless, the poor cycling stability and flexibility of the existing sulfur cathodes, flammable liquid electrolytes, and extremely reactive lithium anodes raise serious battery performance degradation and safety issues. Herein, a metallic 1T MoS and rich oxygen vacancies TiO/MXene hierarchical bifunctional catalyst (Mo-Ti/Mx) anchored on a reduced graphene oxide-cellulose nanofiber (GN) host (Mo-Ti/Mx-GN) was proposed to address the above challenges. By applying a directional freezing process, the hierarchical architecture of a flexible GN scaffold composed of waved multiarch morphology with long-range alignment is achieved. The synergetic effects of 1T MoS and TiO/MXene are beneficial to suppress the shuttling behavior of lithium polysulfides (LiPSs), expedite the redox kinetics of sulfur species, and promote the electrocatalytic reduction of LiPSs to LiS. The electrode demonstrates improved electrochemical properties with high sulfur-mass loading (8.4 mg cm) and lean electrolyte (7.6 μL mg) operation. We also explored the feasibility of producing pouch cells with such flexible electrodes, gel polymer electrolytes, and a robust lithium anode, which exhibited reversible energy storage and output, wide temperature adaptability, and good safety against rigorous strikes, implying the potential for practical applications.
开发具有高能量密度、柔韧性和安全性的锂硫（Li-S）电池，对于新兴的可植入设备、生物监测和可卷曲显示器极具吸引力。然而，现有硫阴极、易燃液体电解质以及极具反应活性的锂阳极的循环稳定性和柔韧性较差，引发了严重的电池性能退化和安全问题。在此，提出了一种锚定在还原氧化石墨烯-纤维素纳米纤维（GN）主体上的金属1T MoS₂和富含氧空位的TiO₂/MXene分级双功能催化剂（Mo-Ti/Mx），以应对上述挑战。通过应用定向冷冻工艺，实现了由具有长程排列的波浪状多拱形形态组成的柔性GN支架的分级结构。1T MoS₂和TiO₂/MXene的协同效应有利于抑制多硫化锂（LiPSs）的穿梭行为，加快硫物种的氧化还原动力学，并促进LiPSs电催化还原为Li₂S。该电极在高硫质量负载（8.4 mg cm⁻²）和贫电解质（7.6 μL mg⁻¹）操作下表现出改善的电化学性能。我们还探索了用这种柔性电极、凝胶聚合物电解质和坚固的锂阳极生产软包电池的可行性，该软包电池表现出可逆的能量存储和输出、宽温度适应性以及对剧烈撞击的良好安全性，这意味着其具有实际应用潜力。
