Article Correlative Confocal Raman and Scanning Probe Microscopy in the Ionically Active Particles of LiMn2O4 Cathodes Denis Alikin 1,*, Boris Slautin 1, Alexander Abramov 1, Daniele Rosato 2,Vladimir Shur 1, Alexander Tselev 3 and Andrei Kholkin 1,3 1 School of Natural Sciences and Mathematics, Ural Federal University, 620000 Ekaterinburg, Russia;
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[email protected]; Tel.: +7-343-261-74-36 Received: 1 April 2019; Accepted: 26 April 2019; Published: 30 April 2019 Abstract: In this contribution, a correlative confocal Raman and scanning probe microscopy approach was implemented to find a relation between the composition, lithiation state, and functional electrochemical response in individual micro-scale particles of a LiMn2O4 spinel in a commercial Li battery cathode. Electrochemical strain microscopy (ESM) was implemented both at a low-frequency (3.5 kHz) and in a high-frequency range of excitation (above 400 kHz). It was shown that the high-frequency ESM has a significant cross-talk with topography due to a tip-sample electrostatic interaction, while the low-frequency ESM yields a response correlated with distributions of Li ions and electrochemically inactive phases revealed by the confocal Raman microscopy. Parasitic contributions into the electromechanical response from the local Joule heating and flexoelectric effect were considered as well and found to be negligible.