The National Institute of Materials Research (NIMS) recently announced that one of their research groups has successfully synthesized materials in which manganese oxide nanosheets and graphene are alternately overlapped.
As a negative electrode material for lithium and sodium ion rechargeable batteries, the composite material can increase the charge and discharge capacity of the battery by more than two times, and can prolong the repeated service life, thereby solving the problem that both capacity and life cannot be achieved.
New anode material makes rechargeable battery capacity long and long
High-capacity is one of the goals of secondary batteries. At present, the negative electrode uses a carbon material. Theoretically, the transition metal oxide has a high capacity and is expected to be a substitute for carbon materials.
In particular, manganese oxide having a layered structure is peeled off into a single-molecular-weight nanosheet, and as a negative electrode, the surface is all active, and the capacity can be greatly increased. However, the difficulty of manganese oxide is that it is easy to break the structure by repeated charge and discharge, and the nanosheets are also likely to aggregate into a mass.
The team dispersed the manganese oxide nanosheets in solution and mixed them with graphene to synthesize an interactive multilayer laminate.
Both manganese oxide and graphene are negatively charged and normally repel each other. The research team solved the repulsion problem by chemically modifying graphene to positively charge it in 2015, and achieved the highest capacity and longest life in the metal oxide anode material at that time.
This time, by combining the two substances from the molecular level, high characteristics that are difficult to achieve with individual materials are obtained. In addition to being used in rechargeable batteries, composite materials can significantly improve the performance of energy storage and conversion systems such as supercapacitors and electrode catalysts.