Our recent post, Where Will All the Lithium Needed for Electric Cars Be Mined? reported on the growing demand for lithium to make lithium-ion (Li-ion) batteries for the electric car market. Companies such as Tesla, Apple, Google, and Faraday Future are expected to build battery factories that could demand as much as 100,000 tons of new lithium carbonate by 2021.
Lithium ion batteries are obviously associated with lithium, but one of the classical anode materials for Li-ion batteries is graphite. There is actually 10 to 30 times more graphite than lithium in a lithium-ion battery. Industrial Minerals reports that Tesla’s “gigafactory” is not only contributing to the increased demand for lithium but that the facility “could potentially increase natural graphite demand by up to 37% by 2020…Tesla’s plant will consume at least 28,000 tonnes of spherical graphite every year if operating at capacity. This equates to 93,000 tonnes of flake graphite if produced to today’s standards which sees raw material wastage of up to 70%.”
Given the impending spike in demand, Graphite Investing News raises the question of whether graphite mining will resume in the United States. The article points out that many investors are looking to North America for graphite investing opportunities, since Tesla Motors’ announcement that it plans to source the lithium, graphite and cobalt it needs for its gigafactory from companies working on the continent.
Regardless of where the raw materials come from, battery manufacturing requires rigorous testing of the batteries and their individual components to ensure they are operating at peak efficiency. Even though a substantial amount of work has been done on the development and commercialization of lithium-ion batteries, there is still considerable interest in improving the current technology and the development of new battery components. The analysis of battery components is important not only for the development of new materials but also for the study of charge/discharge mechanisms and even for confirming the quality of materials used in battery production. The complex nature of batteries requires a multifaceted combination of electrochemical analyses and materials characterization techniques. Raman spectroscopy has emerged as an important analytical technique that can be used for characterizing a variety of battery components.
While graphite is widely used as an anode material for rechargeable Li-ion batteries, other allotropes of carbon besides graphite have been investigated for anode materials due to their novel physical and chemical properties. Raman spectroscopy is an excellent choice for analyzing the different allotropes of carbon. Many of these carbon allotrope materials are strong Raman scatters and have diagnostic spectral features. Raman spectra not only can be used to distinguish different allotropes of carbon but also can provide additional information on the molecular structure. For example, Raman spectral data can be used to determine the number of sheets of graphene in a stack, it can provide information on defects and disorder in the structure of graphene, and it can be used to determine diameters of single wall carbon nanotubes. Raman spectroscopy can also be used to monitor changes in anode materials during use.
For more examples demonstrating the effectiveness of Raman spectroscopy for analyzing anode materials for Li-ion batteries, read Raman Analysis of Lithium-Ion Battery Components – Part II: Anodes.
Other recommended reading:
- Raman Analysis of Lithium-Ion Battery Components: Cathodes
- Raman Analysis of Lithium-Ion Battery Components – Part III: Electrolytes
- In situ Raman Analysis of Lithium Ion Batteries
- Ex Situ Raman Analysis of Lithium Ion Batteries