Harizanova Sonya, Uzunov Ivan, Aleksandrov Lyubomir, Shipochka Maria, Spassova Ivanka, Kalapsazova Mariya
Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
Materials (Basel). 2024 Feb 22;17(5):1016. doi: 10.3390/ma17051016.
The key technological implementation of sodium-ion batteries is converting biomass-derived hard carbons into effective anode materials. This becomes feasible if appropriate knowledge of the relations between the structure of carbonized biomass products, the mineral ash content in them, and Na storage properties is gained. In this study, we examine the simultaneous impact of the ash phase composition and carbon structure on the Na storage properties of hard carbons derived from spent coffee grounds (SCGs). The carbon structure is modified using the pre-carbonization of SCGs at 750 °C, followed by annealing at 1100 °C in an Ar atmosphere. Two variants of the pre-carbonization procedure are adopted: the pre-carbonization of SCGs in a fixed bed and CO flow. For the sake of comparison, the pre-carbonized products are chemically treated to remove the ash content. The Na storage performance of SCG-derived carbons is examined in model two and three Na-ion cells. It was found that ash-containing carbons outperformed the ash-free analogs with respect to cycling stability, Coulombic efficiency, and rate capability. The enhanced performance is explained in terms of the modification of the carbon surface by ash phases (mainly albite) and its interaction with the electrolyte, which is monitored by ex situ XPS.
钠离子电池的关键技术实施是将生物质衍生的硬碳转化为有效的负极材料。如果能够适当了解碳化生物质产物的结构、其中的矿物灰分含量与钠存储性能之间的关系，这将变得可行。在本研究中，我们研究了灰相组成和碳结构对废咖啡渣（SCG）衍生的硬碳的钠存储性能的同时影响。通过在750°C对SCG进行预碳化，然后在Ar气氛中于1100°C退火来改变碳结构。采用了两种预碳化程序变体：在固定床中以及在CO气流中对SCG进行预碳化。为了进行比较，对预碳化产物进行化学处理以去除灰分。在模型二和模型三的钠离子电池中研究了SCG衍生碳的钠存储性能。结果发现，含灰碳在循环稳定性、库仑效率和倍率性能方面优于无灰类似物。通过灰相（主要是钠长石）对碳表面的改性及其与电解质的相互作用来解释性能的增强，这通过非原位XPS进行监测。
