蔗渣
多孔性
阳极
材料科学
吸附
化学工程
热解
碳纤维
电化学
钠
比表面积
复合材料
电极
复合数
化学
制浆造纸工业
冶金
有机化学
催化作用
物理化学
工程类
作者
Kaihua Yu,Xinran Wang,Hongxun Yang,Ying Bai,Chuan Wu
标识
DOI:10.1016/j.jechem.2020.07.025
摘要
A great deal of attention has been paid on developing plant-derived hard carbon (HC) materials as anodes for sodium-ion batteries (SIBs). So far, the regulation of HC has been handicapped by the well-known ambiguity of Na+ storage mechanism, which fails to differentiate the Na+ adsorption and Na+ insertion, and their relationship with the size of d-interlayer spacing and structural porosity. Herein, bagasse-derived HC materials have been synthesized through a combination of pyrolysis treatment and microwave activation. The combined protocol has enabled to synergistically control the d-interlayer spacing and porosity. Specifically, the microwave activation has created slit pores into HC and these pores allow for an enhanced Na+ adsorption with an increased sloping capacity, establishing a strong correlation between the porosity and sloping capacity. Meanwhile, the pyrolysis treatment promotes the graphitization and it contributes to an intensified Na+ insertion with an increased plateau capacity, proving that the plateau capacity is largely contributed by the Na+ insertion between interlayers. Therefore, the structural regulation of bagasse-derived HC has provided a proof on positively explaining the Na+ storage with HC materials. The structural changes in the pore size distribution, specific surface area, d-interlayer spacing, and the electrochemical properties have been comprehensively characterized, all supporting our understanding of Na+ storage mechanism. As a result, the HC sample with an optimized d-interlayer spacing and porosity has delivered an improved reversible capacity of 323.6 mAh g−1 at 50 mA g−1. This work provides an understanding of Na+ storage mechanism and insights on enhancing the sloping/plateau capacity by rationally regulating the graphitization and porosity of HC materials for advanced SIBs.
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