用于钾基能源存储的石墨材料研究进展

Progress on graphitic carbon materials for potassium-based energy storage

  • 摘要: 由于钾离子电池成本低和其电化学性能与锂离子电池相当,钾离子电池和钾基双离子电池成为非常有潜力的新兴储能器件。另外,石墨作为已成功商业化应用的锂离子电池负极材料,也可容纳半径较大的钾离子和一些阴离子的插层并表现出较高的理论容量。但是,石墨材料在钾基能源存储器件中的应用依然面临一些挑战,如半径较大的离子插层会造成较大的体积膨胀(K+>61%;阴离子>130%),导致在循环过程中石墨层间滑移,电池容量衰减;同时由于石墨材料有限的层间距,半径较大的离子会表现出缓慢的插层反应动力学而导致较差的倍率性能。因此,针对存在的问题,本文总结了近年来石墨材料应用于钾基能源存储的研究进展,分析了插层机理并揭示了电化学性能与石墨结构,电解液和黏结剂之间的关系。最后,总结并展望了石墨材料在钾基能源存储中应用的发展方向。

     

    Abstract: Potassium ion batteries (KIBs) and potassium-based dual ion batteries (KDIBs) are newly-emerging energy storage devices that have attracted considerable attention owing to the low-cost of potassium resources and their comparable performance to lithium-ion batteries (LIBs). Graphite materials, as the successful commercialized anode materials of LIBs, can also be used as anodic and cathodic host materials for the intercalation of the large potassium cations and other anions, respectively. However, there are still some challenges hindering the practical application of graphite materials in the anode for KIBs and the cathode for KDIBs. The huge volume changes after intercalation (61% for K and 130% for anions) result in graphite interlayer slipping and structural collapse, causing capacity fade and a short cycle life. Moreover, the intercalation of large K+ and anions have poor kinetics due to the small graphite interlayer spacing, restricting the rate capability. To solve these issues of the use of graphite materials, this review attempts to provide a better understanding of the intercalation mechanisms for K+ and anions, and to correlate the electrochemical performance of KIBs and KDIBs to the microstructure of graphite, and the physicochemical properties of electrolytes and binders. Finally, research prospects are provided to guide the future development of graphite materials for potassium-based energy storage.

     

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