In operando XAFS characterization of cathode materials used in Li-ion batteries

GÓMEZ, SOFÍA; SANSERVINO, MIGUEL A.; VISINTIN, ARNALDO; JORI, KHALIL; GIOVANETTI, LISANDRO J.; REQUEJO, FELIX G.; THOMAS, JORGE E.; AZEVEDO, GUSTAVO

Workshop; IWLiME 2020 7 th International Workshop on Lithium, Industrial Minerals and Energy; 2020

Li-ion batteries have an unmatchable combination of affordable cost, high energy storage capabilities and power density, making it the technology of choice for portableelectronics, power tools, and hybrid/full electric vehicles [1]. Due to the increasing future energetic and efficiency demands some characteristics of these batteries must beimproved. Li-ion batteries electrochemistry performance, life cycle and security conditions are some of these features. To overcome these challenges it is mandatory to have abetter comprehension of the physicochemical processes associated to the Li intercalation during the charge/discharge process. This understanding demands most than ever inoperando characterization and combination of several techniques. The task difficulty is increased by Li reactivity that suppose the need a controlled atmosphere free of O2 or H2O.In order to overcame these challenges we develop a cell that allows to characterize by XAFS in operando condition and at the same time perform a potential or current sweep asneeded.In this work we present an exhaustive characterization by several conventional techniques (TEM, XPS, XRD, etc) in combination with XAFS characterization performed in operandoof materials used Li ion batteries based on Ni and Mn mixed oxides doped with different amounts of Ti (LMNO doped cathodes). The In-operando measurements at the Mn andNi K-edge XANES were obtained at the DXAS beamline of Laboratorio Nacional de Luz Sincrotron (LNLS). Ex situ Ti K-edge EXAFS measurements were performed at XAFS2 beamlineof LNLS in order to correlate the increase in electrode resistance to cell cycling number with Ti incorporation.