Microwave-Induced Nitrogen-Plasma Mass Spectrometric Analysis of Cathodic Materials for Lithium-Ion Batteries
- Lithium-ion batteries (LIBs) are multi-component devices ubiquitously used for powering small consumer devices as well as in the electric mobility sector and for energy storage. From the first successful test in 1986, LIBs performances have improved substantially, doubling their specific energy from 120 to 270 Wh kg−1 in about 30 years, while mass production contributed to a decline of about 98% of their price. The demand is set to grow steadily and is expected to lead to further improvements in performance and falls in prices. [1] In view of the current clean energy transition, the extensive use of this technology is accompanied by an increase of end-of-life LIBs, containing critical minerals for the production of new batteries. The recycling of exhausted batteries is a topic destined to draw increasing attention, and for this purpose, LIBs composition determination is a crucial premise.
While the first commercialized LIB contained about 60% cobalt by mass, the current trend is toLithium-ion batteries (LIBs) are multi-component devices ubiquitously used for powering small consumer devices as well as in the electric mobility sector and for energy storage. From the first successful test in 1986, LIBs performances have improved substantially, doubling their specific energy from 120 to 270 Wh kg−1 in about 30 years, while mass production contributed to a decline of about 98% of their price. The demand is set to grow steadily and is expected to lead to further improvements in performance and falls in prices. [1] In view of the current clean energy transition, the extensive use of this technology is accompanied by an increase of end-of-life LIBs, containing critical minerals for the production of new batteries. The recycling of exhausted batteries is a topic destined to draw increasing attention, and for this purpose, LIBs composition determination is a crucial premise.
While the first commercialized LIB contained about 60% cobalt by mass, the current trend is to lower the Co content by the use of lithium nickel manganese cobalt (NMC) oxide as cathodic material (ca. 6% Co), increasing the cell-specific energy and reducing the raw material price. [2] Besides the change in the layered transition metal oxide composition, elemental substitution, surface treatment and concentration gradient structures, used to increase battery performances, further contribute to increase the cathodic material complexity. [3]
In this work, the composition of several commercial NMC oxides was investigated by Microwave-Induced Nitrogen-Plasma Mass Spectrometry, suitable for the trace analysis on these materials due to its high matrix tolerance in presence of high concentration of transition metals and the easy-to-ionize lithium. [4] Additionally, the effects of different gas flows and ion optics on the matrix tolerance were studied. The method was validated by analyzing BAM-S014 (NMC oxide) as reference material and allowed the generation of a library for such metal oxides. Determination of their exact elemental composition helps users to predict the properties of the cathodic material (e. g. presence of particles coating, additives, or doping elements), and at the same time allows the design of safe recycling procedures, which must consider the presence of health and environment hazardous elements such as uranium, cadmium, or other heavy metals.…

