锂硫电池正极材料的制备及工艺优化

doi:10.13208/j.electrochem.191227

摘要/Abstract

摘要：

锂硫电池具有能量密度高、价格低等优势,有希望应用于下一代储能领域. 但锂硫电池仍然存在一些问题,如多硫化物穿梭效应、缺乏有效的锂硫电池规模制备工艺等. 为了解决这些问题,作者以不同商用碳材料（乙炔黑、科琴黑与碳纳米管）和单质硫复合作为正极材料,探究正极制备工艺对多硫化物穿梭效应抑制效果及锂硫电池性能的影响. 通过研究,作者得出以下结论：科琴黑作为单质硫的载体,与单质硫球磨8 h后,匹配粘结剂聚乙烯吡咯烷酮（PVP）制备的正极浆料可实现在涂布和辊压后极片的厚度达到500 μm、压实密度达到991.65 mg·cm ^-3. 作者将最终得到的正极极片应用于高硫载量锂硫软包电池,电池首圈放电容量为137.4 mA·h,经过10圈循环后,放电容量为115.5 mA·h,表现出优异的电化学性能. 该碳硫复合正极材料制备工艺有望在锂硫电池的宏量制备中获得应用.

关键词: 高能量密度, 锂硫电池, 碳硫复合材料, 厚涂布

Abstract:

Lithium-sulfur (Li-S) batteries represent promising candidates for next-generation energy storage system due to their high energy density and low material cost. However, the industrial application of Li-S batteries remains challenges because of the shuttle effect from lithium polysulfides and the lack of facial routes for Li-S battery preparation. To solve these problems, a cathode consisting of different commercial carbon materials, namely, acetylene black (SP), Ketjen Black (KB) and carbon nanotube (CNT), with sulfur (S) is prepared separately for Li-S battery. After the process of 8-h ball milling for KB/S composite, together with the polyvinyl pyrrolidone (PVP) binder, the cathode could be controlled to yield large thickness (500 μm) and high tap density (991.65 mg·cm ^-3). Accordingly, the as-prepared Li-S pouch cell showed a high electrochemical performance with the discharge capacity up to 137.4 mA·h at the first cycle and the capacity retention up to 84% at the 10th cycle. Over all, we adopt a simple method to solve the serious and challenging problems from the perspective of industrialization in Li-S batteries. The advantages of this simple preparation technology include the optimized formula and process of positive electrode, the easily available component in industry, and the potential mass production. Furthermore, the most suitable electrode could be used to assemble Li-S pouch cell with high surface loading and high capacity. It would shed light on future development of high performance cathode in Li-S batteries, as well as other energy storage systems.

Key words: high energy density, Li-S battery, carbon/sulfur composite material, thick coating

中图分类号:

O646

吴凯. 锂硫电池正极材料的制备及工艺优化[J]. 电化学（中英文）, 2020, 26(6): 825-833.

WU Kai. Preparation and Process Optimization of Cathode Materials for Lithium-Sulfur Batteries[J]. Journal of Electrochemistry, 2020, 26(6): 825-833.

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