| Abstract [eng] |
The demand on energy has been irreversibly increasing over time and the main energy sources up to date are fossil-based. In 2020, only 21% of electrical and 10% of overall energy was produced from renewable sources. The main advantage of these sources a price, however, due to significant contribution to greenhouse gasses, it faces strong social and political pressure. This coupled with the decreased price on solar and wind power technologies are making renewable energy more attractive, however, the absence of energy storage devices remains a bottleneck for fully utilizing produced energy. Rechargeable Lithium-ion batteries are among the most common commercial energy storage devices, but when it comes to large-scale storage, their advantages, such as high power and energy density, are less important than price and safety of operation. Both of these problems can be resolved by using cheap sodium as a charge carrier and non-toxic aqueous electrolytes. Traditionally, such set-up was limited by a narrow potential window, but recently developed water-in-salt electrolytes are making aqueous batteries a viable option. Another factor limiting the usage of aqueous Na-ion batteries is an absence of stable, high voltage cathode materials. Among viable alternatives, NASICON-structured Na3MnTi(PO4 )3 (NMTP) reported by Goodenough et al. as well as Na3V2 (PO4 )2F3 (NVPF) show high operating voltage, capacity and stability in organic media. However, material degradation in aqueous electrolytes remains a major issue. Here the operating process & degradation was studied in 1M Na2SO4 electrolyte using a rotating ring-disc electrode (RRDE). |
