Single-Particle Elemental Analysis of μm-Sized Battery Materials by Laser Ablation Inductively Coupled Plasma Mass Spectrometry

Abstract

Lithium-nickel-manganese-cobalt-oxides (NCMs) represent a preeminent class of cathode active materials for employment in commercially available lithium-ion battery applications. To realize large-scale production of the respective NCM precursors, coprecipitation is often conducted in continuous stirred-tank reactors (CSTR). However, precursors coming from CSTR processes show broad particle size distributions and undesired compositional differences within and between particles. To quantify this phenomenon, it is necessary to develop analytical tools to access quantitative data on particle composition depending on their size. Here, we demonstrate a novel application of single particle laser ablation-inductively coupled plasma-mass spectrometry to determine particle size-dependent elemental compositions by exemplary investigation of CSTR-based NCM precursors. An enrichment of Ni in larger particles with a concomitant enrichment of Co and Mn in smaller particles was identified. This compositional differences between particles persisted after calcination of the precursors with lithium hydroxide. The observed particle size-dependent concentration differences by spLA-ICP-MS were validated by scanning electron microscopy with energy-dispersive X-ray analysis.