ヘテロ原子置換型炭素材料への電気化学インターカレーションと二次電池への応用

抄録

The aim of this thesis is to evaluate boron/carbon/nitrogen (B/C/N) and boron/carbon (B/C) materials as anodes of lithium (Li) and sodium (Na) ion secondary batteries. Boron atoms in the B/C/N and B/C materials improved crystallinities of these materials. Potentials at the beginning of discharge (intercalation of Li⁺ ion) of these materials were higher than those of graphite, low crystalline carbon and carbon/nitrogen material, which was also influenced by the boron atoms in B/C/N and B/C materials. The B/C material, which was prepared at 1170 K with the molar ratio of BCl₃ : C₂H₄=1 : 3, showed the highest reversible capacity 516 mA h g⁻¹ in 1 M-LiPF₆/EC+DEC among the materials prepared in this study. The formation of stage structures was observed during the discharge (intercalation of Na⁺ ion) in 1 M-NaPF₆/EC+DEC electrolyte solution, which was not clearly observed in the case of hard carbon and low crystalline carbon. The B/C material, which was prepared at 1270 K with the molar ratio of BCl₃ : C₂H₄=1 : 3, showed the highest reversible capacity 238 mA h g⁻¹ in 1 M-NaPF₆/EC+DEC among the materials prepared in this study. When we evaluated these materials as dual carbon alloy batteries, the maximum capacity of 487 mA h g⁻¹ was observed for a battery with a combination of B/C material anode (intercalation of Li⁺ ion) and graphite cathode in 1 M-LiPF₆/EC+DEC, while the maximum capacity of 272 mA h g⁻¹ was observed for a battery with a combination of B/C material anode (intercalation of Na⁺ ion) and graphite cathode in 1 M-NaPF₆/EC+DEC.