ABSTRACT
This chapter aims to perform measurements of reaction distribution and separate internal resistances for a composite electrode. It shows the factors that govern the formation of a reaction distribution by integrating and discussing the results. The chapter presents the electrochemical characteristics of several composite electrodes prepared at different electrode porosities and measured the reaction distributions in electrode cross sections using two-dimensional-imaging X-ray absorption spectroscopy. Power storage devices, typified by lithium-ion secondary batteries, are high-efficiency devices for electrochemical energy conversion. The reactions that occur inside lithium-ion secondary batteries involve multiple inter-related phenomena with nonequilibrium condition. Following the reaction at the electrode/electrolyte interface, lithium-ion insertion/extraction occurs within the electrode-active material. As the charge/discharge reaction proceeds, it causes the insertion and extraction of lithium ions within the electrode-active material. The reaction distribution is predicted to be determined by the balance of the electronic current and the ionic current within the composite electrode, and so the two must be examined separately.
