The investigation on the mechanisms governing the function and operation of battery materials, interfaces and interphases, is indissolubly linked to the successful obtainment of long life and high performance LIB systems. Interfacial reactions, which include lithium ion insertion/extraction, decomposition of the electrolyte and formation of a solid electrolyte interphase (SEI) layer determine the irreversible capacity, cycling ability and lifetime of LIBs [1,2]. Among the high energy density anode materials candidates, intermetallic materials e.g., Sn, Si have attracted significant attention as a Li-alloying anode due to their high specific and volumetric capacity as compared to graphite electrodes [3]. However, large irreversible capacity observed during the first cycle, volumetric changes of active material particles during the (de-)alloying process, particle decrepitation and loss of electronic contact in the composite electrode are responsible for the rapid degradation of intermetallic-based anodes in LIB systems. [3-5]. To gain insights into the mechanism of the electrolyte decomposition and SEI layer (re)formation upon cycling we investigated the role of single solvents and additives into the electrolyte. The role of LiF, Li2CO3, LiEDC in the SEI has been investigated through electrochemical tests, such as cyclic voltammetry and galvanostatic polarization and IRNSOM, FTIR, XAS surface characterization. Furthermore, a comparative study to investigate the effect of surface oxide species on tin surface has been carried out and will be discussed during the presentation.

Surface reactivity of Li-ion intermetallic electrodes in organic carbonate electrolyte

256th National Meeting (2018)

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