Extended Viologen Derivatives as Anode Materials for MolecularIon Battery

摘要

Currently,lithium-ion secondary batteries (LIBs) are one of the devices in high demandamong energy storage,and their applications are still expanding in various fields.However,there are resource constraints because conventional LIBs contains lithium ions as chargecarriers and rare metals such as cobalt as electrode materials.When a battery without raremetals or harmful metals is developed,it will be one of the solutions for the problems relatedto environment and energy as well as resource.We have proposed a new rocking-chair-typebattery system using organic compounds composed of elements that are not subject to resourceconstraints,such as carbon,hydrogen,nitrogen,oxygen and sulfur as electrode active materials,in which a molecular ion such as (CH3)4N~+ and PF_6~-works as a charge carrier.In our previousstudy,1 a viologen-type anode material was used;however,its redox potential was not lowenough.In order to obtain a battery with a higher energy density,other anode material whichworks at a lower redox potential is required.