基于碳功能材料的新型室温钠-硫二次电池的研究

Comparing to lithium-ion technology, sodium-ion batteries have the appealing advantages of lower cost and higher safety. As a result, they are promising candidates for future electric vehicles and grid-scale energy storage applications. Unfortunately, currently available cathode and anode materials of sodium-ion batteries generally suffer from limited specific capacity, low rate capability and poor cycling stability. Here, we propose to prepare novel nanoscale electrode materials and fabricate high-performance rechargeable sodium-sulfur batteries that operating at room temperature. This study will focus on chemically exfoliated and modified graphene sheets as the anode material and sulfur-graphene composites as the cathode material. We will evaluate the influence of chemical compositions and physical structures on their electrochemical charge-discharge properties in great detail. Through ex-situ or in-situ XRD, Raman and XANES characterizations, the possible electrochemical reaction mechanism of these electrode materials as well as existing problems will be unraveled and interpreted, and solutions will be sought. This proposal aims at the successful demonstration of rechargeable sodium-ion batteries with large energy/power densities and long cycle life, which will lay the ground for future large-scale applications of sodium-ion batteries.

钠离子电池与现有的锂离子电池相比成本更低和安全性更高，它们有望在未来电动汽车和智能电网储能等领域发挥至关重要的作用。鉴于目前钠离子电池的正负极材料普遍面临着存储容量小、倍率特性低和循环性能差等一系列问题，本申请拟通过制备新型的纳米电极材料来发展高性能的室温钠-硫二次电池体系。重点研究化学法剥落和修饰后的石墨烯作为钠离子电池负极材料的可行性和硫基复合材料作为钠离子电池正极材料的可行性。通过各种电化学测量手段，深入掌握这些电极材料在钠离子电池中的充放电特性，以及材料本身化学成分和物理结构对其电化学性能的影响；同时结合各种原位或异位XRD、Raman和XANES等表征技术研究揭示可能发生的反应机理、存在的问题并提出相应的解决方案。通过对电池材料的制备和优化，实现高能量和功率密度、长循环寿命的室温钠-硫电池，为钠离子电池将来的大规模应用打下一定的基础。

本项目发展了多种二维材料材料自下而上和自上而下的合成方法，实现了材料组分、结构、缺陷的精准调控;采用二维材料作为钠离子电池的负极材料,实现良好的存储容量和循环性能;提出了“类硫”正极材料的概念,解决了传统硫基正极面临的多硫化物溶出的问题,为室温锂/硫、钠/硫电池的发展提供了一种新的可行途径。以通讯作者发表相关论文34篇，包括Nature Communications、Chem、Advanced Materials、PNAS等顶尖杂志，受邀在国内外大会作相关邀请报告20余次，申请中国专利5项，目前授权1项。项目先后资助硕士研究生16人、博士研究生6人。