关键词: 菱角壳, 水热法, 硬炭, 锂离子电池, 负极

Abstract:

With their large layer spacing and controllable pore and defect structures, hard biomass carbon materials are suitable anode materials for lithium ion batteries (LIB). In this paper, impurities were removed from a water-chestnut shell precursor by hydrothermal treatment, which is safer and more environmentally friendly than pickling and saves material preparation time. The hard carbons derived from the water chestnut shells were prepared as the anode materials at different high temperatures (HT-x). The morphologies, microcrystalline structures, and microstructures of the specimens were characterized by scanning electron microscopy, X-ray diffraction analysis, Raman spectroscopy, and transmission electron microscopy. As clarified in the results, the impurities were substantially removed from the precursor. The carbonization temperature significantly affected the microstructure and lithium storage performance of the material. Sample HT-1100 exhibited a large layer spacing (d₀₀₂=0.39 nm) and a moderate specific surface area (76.82 m²/g). Under a current density of 0.1 C (1 C=250 mA/g), the reversible discharge specific capacity of this sample reached 405.6 mA·h/g. The rate performance was also high, with a specific capacity of 181.3 mA·h/g at 4 C. After 300 cycles at a current density of 0.4 C, the capacity remained at 382.5 mA·h/g, showing excellent cycle performance. By applying hard carbon derived from water chestnut shells as the anode material in LIB, we provide experimental support for converting a waste product into a valuable commodity, ultimately realizing green and efficient resource utilization.

Key words: water chestnut shell, hydrothermal method, hard carbon, lithium ion battery, anode