April 2018Lithium-ion-batteries are used in many fields of our daily live due to their high energy- and power density. Usually, graphite anodes and transition metal cathodes are used as electrodes. LiNi1/3Co1/3Mn1/3O2 (NCM) particles are often used as cathode material. Increasing nickel content of the material results in higher capacities at the expense of stability. Doping or coating of the material can mitigate this effect. Time of flight secondary ion mass spectrometry (ToF-SIMS) enables to detect even very low elemental concentrations. This method is applied to investigate whether dopants are incorporated into the material or deposited at the particle surface. The upper image shows a mass image as RGB overlay of the surface of a NCM electrode. A focused ion beam (FIB) was applied to produce a cross section. The NCM particles (oxygen red; lithium blue) are embedded into a carbon matrix (carbon green). This makes it possible to investigate the composition of the surface and the core of the particles. The lower image shows a 3D reconstruction of the oxygen signal, which was measured during a FIB-SIMS-tomography of the sample. (Picture submitted by Jan Binder and Marcus Rohnke.)https://www.uni-giessen.de/en/faculties/f08/departments/physchem/janek/gallerypotm/pom2018/BdM0418.png/viewhttps://www.uni-giessen.de/@@site-logo/logo.png
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April 2018
Lithium-ion-batteries are used in many fields of our daily live due to their high energy- and power density. Usually, graphite anodes and transition metal cathodes are used as electrodes. LiNi1/3Co1/3Mn1/3O2 (NCM) particles are often used as cathode material. Increasing nickel content of the material results in higher capacities at the expense of stability. Doping or coating of the material can mitigate this effect. Time of flight secondary ion mass spectrometry (ToF-SIMS) enables to detect even very low elemental concentrations. This method is applied to investigate whether dopants are incorporated into the material or deposited at the particle surface. The upper image shows a mass image as RGB overlay of the surface of a NCM electrode. A focused ion beam (FIB) was applied to produce a cross section. The NCM particles (oxygen red; lithium blue) are embedded into a carbon matrix (carbon green). This makes it possible to investigate the composition of the surface and the core of the particles. The lower image shows a 3D reconstruction of the oxygen signal, which was measured during a FIB-SIMS-tomography of the sample. (Picture submitted by Jan Binder and Marcus Rohnke.)
