Although much progress has been made to develop high-performance lithium-sulfur batteries (LSBs), the reported physical or chemical routes to sulfur cathode materials are often multistep/complex and even involve environmentally hazardous reagents, and hence are infeasible for mass production. Here, we report a simple ball-milling technique to combine both the physical and chemical routes into a one-step process for low-cost, scalable, and eco-friendly production of graphene nanoplatelets (GnPs) edge-functionalized with sulfur (S-GnPs) as highly efficient LSB cathode materials of practical significance. LSBs based on the S-GnP cathode materials, produced by ball-milling 70 wt % sulfur and 30 wt % graphite, delivered a high initial reversible capacity of 1265.3 mAh g-1 at 0.1 C in the voltage range of 1.5-3.0 V with an excellent rate capability, followed by a high reversible capacity of 966.1 mAh g-1 at 2 C with a low capacity decay rate of 0.099% per cycle over 500 cycles, outperformed the current state-of-the-art cathode materials for LSBs. The observed excellent electrochemical performance can be attributed to a 3D \u22sandwich-like\u22 structure of S-GnPs with an enhanced ionic conductivity and lithium insertion/extraction capacity during the discharge-charge process. Furthermore, a low-cost porous carbon paper pyrolyzed from common filter paper was inserted between the 0.7S-0.3GnP electrode and porous polypropylene film separator to reduce/eliminate the dissolution of physically adsorbed polysulfide into the electrolyte and subsequent cross-deposition on the anode, leading to further improved capacity and cycling stability.
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机译:尽管在开发高性能锂硫电池(LSB)方面已取得了很大进展,但已报道的通向硫阴极材料的物理或化学途径通常是多步骤/复杂的,甚至涉及对环境有害的试剂,因此无法大规模生产。在这里,我们报告了一种简单的球磨技术,将物理和化学路线结合为一个步骤,以低成本,可扩展且生态友好的方式生产了边缘硫化的石墨烯纳米片(GnPs)(S- GnPs)作为高效LSB阴极材料具有实际意义。通过球磨70 wt%的硫和30 wt%的石墨生产的基于S-GnP阴极材料的LSB,在0.1 C和1.5-3.0 V电压范围内,在0.1 C时可提供1265.3 mAh g-1的高初始可逆容量。优异的倍率性能,随后在2 C时具有966.1 mAh g-1的高可逆容量,在500个循环中每个循环的容量衰减率仅为0.099%,其性能优于目前最先进的LSB阴极材料。观察到的优异的电化学性能可以归因于S-GnPs的3D三明治结构,在放电过程中具有增强的离子电导率和锂的插入/提取能力。此外,将由普通滤纸热解的低成本多孔碳纸插入0.7S-0.3GnP电极与多孔聚丙烯膜隔板之间,以减少/消除物理吸附的多硫化物向电解质中的溶解以及随后在阳极上的交叉沉积。 ,从而进一步提高了容量和循环稳定性。
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