Organic Positive-Electrode Materials Based on Dialkoxybenzoquinone Derivatives for Use in Rechargeable Lithium Batteries

The performance of 2,5-dialkoxy-1,4-benzoquinone derivatives as positive-electrode active materials for use in rechargeable lithium batteries was investigated. These derivatives showed stepwise two-electron redox behaviors in cyclic voltammetry, and also exhibited high initial discharge capacities of more than 200 mAh g(-1) in charge/discharge tests. In particular, a positive-electrode that used a methoxy derivative showed the largest discharge capacity (close to 300 mAh g(-1)) among the dialkoxy derivatives tested. These discharge curves imply benzoquinone-based two-electron redox behavior. Theoretical quantum calculations based on the density functional theory (DFT) were also performed to discuss the electrochemical properties of these materials, and supported the experimental results.