Repozytorium publikacji - Politechnika Gdańska

ZnFe2O4 (ZFO) Li-ion batteries (LIBs) represent a reliable, affordable, and safe energy storage technology for use in portable application. However, current LIB active materials (graphite, lithium/transition metal spinel or layered oxides, olivine structures) can store only limited energy since they rely on insertion storage based on solid-state host-guest interactions. Moreover, performances and durability of the cells are strongly influenced by the characteristics of the solid electrolyte interphase (SEI), which is formed upon the electrodes, especially for graphite, during the first charge/discharge cycle. This process is difficult to study and control. The aim of this work is to study the evolution of the SEI in this innovative anode material at selected charging steps by exploiting the surface sensitivity of the soft X-ray absorption spectroscopy (XAS). This technique requires synchrotron radiation and was never used before for such a purpose, although it appears to be very suitable for a detailed depth profiling of the SEI of advanced electrodes. The main conclusions that can be drawn by this work can be summarized as follows: 1) the evolution of the SEI takes place already during the first steps of the charging process and its thickness reach about 40 nm at about 1/3 of the full capacity, with a stable total thickness up to 20 working cycles; 2) the XAS technique is found to be very effective providing an estimate of the local thickness of the SEI, and indicates that the SEI grows preferentially around the ZFO nanoparticles.

Autorzy

• prof. Andrea DiCicco,
• Angelo Giglia,
• Roberto Gunnella,
• Stephan Koch,
• Franziska Mueller,
• Francesco Nobili,
• Marta Pasqualini,
• Stefano Passerini,
• Roberto Tossici,
• dr hab. inż. Agnieszka Witkowska link otwiera się w nowej karcie