Dialkoxybenzoquinone-type Active Materials for Rechargeable Lithium Batteries: The Effect of the Alkoxy Group Length on the Cycle-stability

The performance of 2,5-di-n-decyloxy-1,4-benzoquinone (DDBQ) as an active material for rechargeable lithium batteries was investigated. The prepared electrode in which DDBQ was incorporated showed an initial discharge capacity of 125 mAh/g(DDBQ) with an average voltage of 2.5 V vs. Li+/Li. The obtained discharge capacity corresponds to a benzoquinone-based two-electron redox behavior. In the cycle-life test, the prepared DDBQ- electrode showed a relatively good performance; it maintained about 60% of the initial capacity after 20 cycles. The observed cycle-stability was compared to those of the other dialkoxybenzoquinones bearing shorter alkoxy chains, such as the methoxy, ethoxy, and propoxy groups. The correlation between the cycle-stability and the solubility in the electrolyte solvent was discussed.