Peng Jiao, Wang Huanwen, Shi Xiaojun, Fan Hong Jin
Faculty of Material and Chemistry, China University of Geosciences, Wuhan, 430074, China.
School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
Adv Mater. 2024 Nov 27:e2410326. doi: 10.1002/adma.202410326.
Hard carbon (HC) stands out as the most promising anode material for sodium-ion batteries (SIBs), and a precise adjustment of the pore structure is the key to achieving high plateau-capacity. In this work, composite hard carbon is developed by integrating graphitic carbon with biomass waste (banana peel)-derived activated carbon (AC). In this design, N-doped pseudographite layer is stacked at the entrance of open pores, forming a long-range graphitic layer without excessive graphitization. As a result, the surface area of AC is decreased by 170 times down to less than 10 m g, and the corresponding open pores are in situ converted into closed pores. In an optimized electrolyte solvation structure, the obtained HC anode achieves the reversible sodium-storage capacity up to 524 mAh g. In particular, a large portion of the capacity (490 mAh g) lies below the plateau of 0.25 V, which originates from the pore-filling mechanism as revealed by in situ Raman. This study provides a straightforward method to modulate the pore structure of carbon materials, and an energy-efficient (900 °C) synthesis for HC compared to traditional high-temperature routes (e.g., ≈1300-2000 °C).
硬碳（HC）是最有前景的钠离子电池（SIB）负极材料，精确调节孔隙结构是实现高平台容量的关键。在这项工作中，通过将石墨碳与生物质废料（香蕉皮）衍生的活性炭（AC）相结合来制备复合硬碳。在这种设计中，氮掺杂的准石墨层堆叠在开孔入口处，形成了长程石墨层且没有过度石墨化。结果，AC的表面积降低了170倍，降至小于10 m²/g，相应的开孔原位转化为闭孔。在优化的电解质溶剂化结构中，所得的HC负极实现了高达524 mAh/g的可逆钠存储容量。特别是，大部分容量（490 mAh/g）位于0.25 V的平台以下，这源于原位拉曼光谱揭示的孔隙填充机制。本研究提供了一种直接调节碳材料孔隙结构的方法，以及与传统高温路线（例如，约1300 - 2000°C）相比，HC的节能（900°C）合成方法。
