Feasibility Study Of Biomass Carbon Source Used As Electrode Material

Lithium-ion battery(LIB)has quickly become a hot research in energy storage because of its environment-friendly,high voltage,specific energy and long cycle life.However,as a conventional commercialized anode material for LIBs,graphite exhibits poor theoretical specific capacity(372 mAh g-1),which makes it difficult to meet the further improvement for LIBs with high energy.In this paper,based on three different biomass-derived carbon sources,the surface morphology and microstructure of the carbon materials were regulated via carbonization,graphitization treatment and chemical activation.The morphology and structure were studied using X-ray diffraction,Raman spectrometer,SEM techniques.The coin-type cells were assembled with the prepared carbon as anode material,and the cells were tested with galvanostatic charge-discharge,cyclic voltammograms(CV)and electrochemical impendence spectroscopy(EIS)to verify the influence of the structure on the electrochemical performance.It was found that microalgae-derived material carbonized at 900? exhibited the best electrochemical performance due to its moderate hierarchical pore structure and graphitic structure as well as the integrity and stability of SEI film formed during the charging and discharging process;After heat-treatment at 2800 ?,the obtained BDC-2800 possessed a high degree of graphitization and showed an outstanding cycling performance,delivering capacity decay from 423 to 396 mAh g-1 at 0.1 C after 100 cycles.The chemical-treated carbons also demonstrated enhanced electrochemical performance,especially for the KOH-treated sample.The BDC-K displayed superior specific charge capacity of 801 mAh g-1 at 0.1 C,and showed an impressive rate capability of 643 mAh g-1 at 1 C.In addition,this sample delivered capacity retention of 94% after 500 cycles at 1 C.This good electrochemical performance was mainly owing to its high surface area and abundant mesoporous structure.Similarly,tea seed shell after carbonization-activation showed better electrochemical performance than hydrothermal activation,which is also due to its higher specific surface area and more developed pore structure.