Supply Risks associated with Li-ion battery cathode materials

The reduction of greenhouse gas emissions as well as technological advances will lead to increasing market shares of electric vehicles in the mobility sector and generally increased battery production capacity. Technological... [ view full abstract ]

The reduction of greenhouse gas emissions as well as technological advances will lead to increasing market shares of electric vehicles in the mobility sector and generally increased battery production capacity. Technological challenges for hybrid, plug-in hybrid and battery electric vehicles range from cost reduction and long battery lifetime to rapid recharging and long driving range. For pursuing these targets, a wide range of active materials has been developed in recent years and is currently being produced for this important mobility sector. The same batteries could also be used in other emerging markets like stationary grid applications. Most battery technologies use a graphite anode; various lithium metal oxides are employed for the cathode: The metals can be cobalt (LCO), manganese (LMO), any stoichiometric combination of nickel, manganese and cobalt (NMC), a combination of nickel, cobalt and aluminum (NCA), or the cathode material can be lithium iron phosphate (LFP).

The rapid growth of battery production capacity leads to the question as to whether the raw material requirements for the active materials are associated with a problematic level of supply risk. Such an assessment has previously been made for thin-film photovoltaic systems, which are also expected to show high demand growth (see Helbig et al. 2016, Applied Energy 178, pp. 422-433). Here, we use the same semi-quantitative indicator-based assessment of supply risks to evaluate the different Li-ion cathode options. We evaluate each of the functional elements used with respect to eleven indicators in the following categories: risk of supply reduction, risk of demand increase, concentration risk and political risk. Subsequently, the individual indicator scores are aggregated to a single supply risk score on the element level. Applying four aggregation possibilities at the technology level, we compare the supply risks for different Li-ion battery types.

Our results show that supply risks are mainly linked to Li and Co. Therefore, the trend towards nickel-cobalt-aluminum (NCA) and lithium-manganese-rich nickel-manganese-cobalt (LMRNMC) materials and their reduced Co content has partially lowered the overall supply risk. In contrast, the risk of lithium raw material supply shortages is persistent. The increased share of Li, both in terms of mass and value, even increases its impact on the supply risk at the technology level. As all present technologies rely on Li as charge carrier material, our results highlight the importance of measures to ensure security of supply, to increase resilience and to anticipate higher raw material prices.