Elektrocheminės medžiagotyros seminaras:
Improving Rate Capability of Electrodes for Lithium and Sodium Ion Batteries
Gints Kucinskis (Insitute of Solid State Physics, University of Latvia, Latvija)
Both Li and Na-ion batteries are based on reversible insertion and extraction of mobile ions into the crystal structure of electrode materials. In a battery, the reaction rate depends on properties of the insertion materials (electron and ion transport within the active material) as well as electrode architecture (electron and ion transport to and from the active material).
We first look at transport phenomenon within LiFePO4 – electronic conductivity in lithium-rich and poor phases of LixFePO4. Although Yamada et al. have reported that both phases possess differing electronic conductivities, we find no proof of this in our measurements, likely due to minor compositional differences. We also find no signs of measurably improved interfacial conductivity in lithium-rich LiFePO4 phase.
Next, we turn to electrode architecture. LiFePO4/reduced graphene composite was studied as means of improving rate capability. Results shown that mixing oder of the graphene oxide additive and active material are of crucial importance. Both capacity and rate capability are improved when mixing graphene oxide with the precursor at the initial stages of synthesis. We also observe Na2FeP2O7 cathode for sodium-ion batteries to greatly benefit from external electron-conducting carbon network and plan to look into phase transitions within the material in the near future.
2020-02-06 11:00 / NFTMC Saulėtekio al. 3, E302