In-situ measurement of the lithium distribution in Li-ion batteries using micro-IBA techniques

Direct observation of lithium concentration distribution in lithium-ion battery composite electrodes has been performed for the first time. Lithium-ion battery model cells for particle induced X-ray emission (PIXE) and particle induced gamma ray emission (PIGE) measurements were designed and fabricated. Two dimensional images of lithium concentration in LiFePO4 composite electrodes were obtained with PIXE and PIGE by scanning the proton microbeam for various charged states of the electrodes. Lithium concentration in LiFePO4 composite electrodes was decreased from the contact interface between LiFePO4 electrode and liquid electrolyte during the charge reaction.