In-operando electrochemical cell for X-ray absorption studies on lithium-ion batteries.

J.E. THOMAS; L.J. GIOVANETTI; M.A. SANSERVINO; G. AZEVEDO; F.G. REQUEJO; A. VISINTIN

Bologna

Congreso; 69th Annual Meeting of the ISE; 2018

International Society of Electrochemistry

A clear comprehension of the processes that occurs during the use of Lithium based batteries is indispensable to improve the performance and efficiency of these systems. Sometimes, it is not possible to detect all the physicochemical processes only using electrochemical measurements, and in the case of lithium ion batteries, the possibility to make electrochemical experiments in a classical tree electrodes cell joined to other chemical or physical techniques is very hard. Typical impediments to this type of experiment are, for example, the nature of the electrodes, electrolytes and working conditions of these types of batteries. For this reason we develop an in-operando lithium ion battery cell system capable to work in typical current/potentials experiments for these kinds of batteries and at the same time allow performing X-Ray absorption or diffraction experiments over the active materials.Whit this setup it is now possible to characterize different anodic and cathodic active materials by X-ray spectroscopy techniques like XANES and EXAF at different working conditions i.e. different states of charge (SOC) or during a potentiodynamic running and also under normal operation conditions like charge-discharge cycles. The aim of this work is focused the use of the same electrochemical cell not only to XAFS but also to other types of techniques (XRD, XRF, etc) working at faster potentiodynamic experiments or higher current conditions. In this work we present ours recent results obtained in the DXAS beam line at the LNLS with a home made 5 Volts spinel (LiNi0,5Mn1,5O4) cathode under working conditions. Figure 1(a) shows a picture of the in-situ cell ensemble (inside of the adapter) ready to work in the beam line. Figure 1(b) and 1(c) shows the XANES spectra of during a discharge and the PCA-XSAF fit whit the discharge potential profile of Ni and Mn K-edges respectively.