| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2016) | |
| Energy Harvesting & Storage | Wednesday Sessions |
| Session EH-WeP |
| Session: | Energy Harvesting & Storage Poster Session |
| Presenter: | Yuki Matsushita, Kansai University, Japan |
| Correspondent: | Click to Email |
The electrochemical energy storage devices have attracted an attention in the field of mobile electric devices and electric vehicles. Lithium-ion batteries are one of the most significant devices because of high energy density, high output voltage, and no memory effect.
The primary components of a lithium-ion battery are negative-electrode material, positive-electrode material, separator, and electrolytes along with current collectors. Lithium-ion batteries operate through the migration of lithium- ions between the electrodes. During charging and discharging, electrode reactions occur in the active materials corresponding to lithium-ion migrations.
The active materials in the electrodes of the lithium-ion batteries have been commonly used LiCoO2 and graphite that were layered materials. Also, the electrolyte is a lithium salt in an organic solvent. The lithium-ion batteries based on graphite are approaching the theoretical limit for capacity. Therefore, Si particles have attracted an attention. Si has a high theoretical specific energy density for anode materials in lithium-ion batteries. However, the cycle life of batteries with Si anode is poor as large volume changes are associated with the lithiation and delithiation cycle according to electrode reactions, resulting in the pulverization of the electrode. In addition, lithium-ion batteries have a risk of ignition because of using flammable organic liquid electrolyte. All-solid-state lithium-ion batteries using the non-flammable inorganic solid electrolyte instead of flammable organic liquid electrolyte have been attracted an attention to improve safety. Lithium-ion batteries have been widely studied for additional improvement of performance and safety.
When Si or Li2TiO3 particles lithiated or delithiated with lithium ions in a battery, the electrons also are transferred to maintain charge neutral. Therefore, the anode materials in the electrodes of the lithium-ion batteries are required to both electronic conductivity and ionic conductivity. We focused on change in electronic properties of the anode materials especially Si due to the chemical reactions with lithium ions. We present results in observation of changes in electric properties of Si particles in the anode corresponding to the lithium-ion concentrations, which were obtained via a scanning probe microscope.