First results of in-situ X-ray Absorption Spectroscopy study on charging-discharging cycles of lithium ion battery at Indus-2 SRS

Abstract

An electrochemical cell with Kapton X-ray windows has been in-house developed and related facilities have been set-up for in-situ X-ray Absorption Spectroscopy (XAS) measurements on electrode materials of Li-ion batteries at the Energy Scanning EXAFS beamlines (BL-09) at Indus-2 Synchrotron Source at Indore, India. The set-up has been tested by carrying out in-situ XAS measurements at Mn K-edge on a Li-ion battery with LiMn2O4 as cathode material during charging and discharging when Li ions are de-intercalated and intercalated respectively. The in-situ XAS measurements, (which comprise of both XANES and EXAFS measurements) reveal electronic and structural changes at the Mn sites of the cathode material during the charging/discharging processes which are not fully reversible. Such in-situ studies are very important since cyclic instability of batteries during the charging/discharging processes depend on the variation in the local structure around the active atoms of the electrode materials and thus the above facility would open up a new avenue to the users of Indus-2 synchrotron facility at India in elucidating such phenomena in new generation batteries with novel electrode materials.