Power storage of a secondary battery is performed by desorbing ions from the electrode material, which is the heart of the battery.The more ions are desorbed from the electrode material, the more power can be stored, but with conventional electrode materials, desorption of ions destabilizes and changes the structure, resulting in reduced performance. ..That is, the structure deteriorates due to repeated charging, which causes the battery life to be shortened.

　In this research, we have discovered an electrode material that changes to a stable structure by charging, which is completely opposite to the conventional electrode material.It is said that the structural disorder of this electrode material disappears spontaneously each time it is charged (ion desorption), and even if the electrode material is repeatedly charged and discharged for a long period of time with a large load, it will self-charge each time it is charged. There was almost no deterioration in performance due to repairs.

　As a result of detailed analysis of the phenomenon, it was found that a strong Coulomb attraction acts between the pores generated after the desorption of ions and the ions remaining inside the substance.When the vacancies and ions are strongly attracted to each other, they spontaneously change to a structure without disturbance and self-repair.

　If this Coulomb attraction is introduced, self-repairing ability may be exhibited in other electrode materials.With the progress of social introduction of environment-friendly technologies such as electric vehicles and wind power / solar power generation, this result is expected to extend the life of secondary batteries, which are expected to be responsible for the storage and supply of electricity in energy networks. ..

Paper information:[Nature Communications] Coulombic self-ordering upon charging a large-capacity layered cathode material for rechargeable batteries