Yao Masaru, Sano Hikaru, Ando Hisanori, Kiyobayashi Tetsu, Takeichi Nobuhiko
Research Institute of Electrochemical Energy, Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka, 563-8577, Japan.
Chemphyschem. 2019 Apr 2;20(7):967-971. doi: 10.1002/cphc.201900012. Epub 2019 Mar 7.
An anthraquinone (AQ)-based dimer and trimer linked by a triple bond (-C≡C-) were newly synthesized as active materials for the positive electrode of rechargeable lithium batteries. These synthesized oligomers exhibited an initial discharge capacity of about 200 mAh g with an average voltage of 2.2-2.3 V versus Li . These capacity values are similar to that of the AQ-monomer, reflecting the two-electron transfer redox per AQ unit. Regarding their cycling stability, the capacity of the monomer electrode quickly decreased; however, the electrodes of the prepared oligomers showed an improved cycling performance. In particular, the discharge capacities of the trimer remained almost constant for 100 cycles. A theoretical calculation revealed that the intermolecular binding energy can be increased to the level of a weak covalent bonding by oligomerization, which would be beneficial to suppress the dissolution of the organic active materials into the electrolyte solutions. These results show that the cycle-life of organic active materials can be extended without lowering the discharge capacity by the oligomerization of the redox active molecule unit.
一种基于蒽醌（AQ）、通过三键（-C≡C-）连接的二聚体和三聚体作为可充电锂电池正极的活性材料被新合成出来。这些合成的低聚物在相对于锂的情况下，初始放电容量约为200 mAh g，平均电压为2.2 - 2.3 V。这些容量值与AQ单体的容量值相似，反映了每个AQ单元的双电子转移氧化还原过程。关于它们的循环稳定性，单体电极的容量迅速下降；然而，所制备的低聚物电极表现出改善的循环性能。特别是，三聚体的放电容量在100次循环中几乎保持恒定。理论计算表明，通过低聚作用，分子间结合能可以提高到弱共价键的水平，这将有利于抑制有机活性材料溶解到电解质溶液中。这些结果表明，通过氧化还原活性分子单元的低聚作用，可以在不降低放电容量的情况下延长有机活性材料的循环寿命。
