ナノリチウムイオン電池のオペランドTEM観察

抄録

It has been one of the key issues to understand the lithium transport in the cathodic materials during the lithium ion battery operation at high charge-discharge rate. Operando transmission electron microscope (TEM) observation is a power method to solve this problem, since such dynamics has been suggested to be a kind of nonequilibrium behaviors. We developed nanobatteries consisting of LiMn₂O₄ nanowires cathode, liquid ion electrolyte and Li₄Ti₅O₁₂ crystalline anode for operando TEM observation. By taking electron diffraction patterns of the cathode in the vicinity of the interface, we found that the cubic phase of the LiMn₂O₄ nanowire changed into two phases of the cubic and orthorhombic phases and finally into the tetragonal phase during discharging process. It suggests that a lot of lithium ions must be accumulated in the vicinity of the interface with the electrolyte. We also investigated the lithium ion transport inside the nanowire cathode.