## 3 Results
### Sensitivity Analysis  
The aim of the sensitivity analysis is to determine the effect of the selected parameters on the cumulated amount of secondary material available, thereby validating the robustness of the results [45]. These are selected due to the uncertainty in either the current assumptions, or in the potential development of the parameters in the future.  
The analysis is based on the following parameter variations, which potentially reduce the amount of recoverable LIB materials in different ways:  
* Increasing LIB lifetime by 10%, i.e., 11 years instead of 10 years, thereby delaying LIB recycling.
* Increase the share of LIB entering 2 nd life from 5% to 15%, thereby reducing the number of LIBs available for recycling.
* Reducing the share of LIBs entering an efficient hydrometallurgical recycling process by 10%. These LIB instead enter a less efficient pyro-metallurgical recycling, leading to a lower amount of recovered material.
* Reducing the amount of production waste by 10%, thereby lowering the number of LIBs entering recycling.  
Figure 4: Comparison of scenarios (Sc) regarding cobalt (Co) trend with Bloomberg (BLO) and IHS forecast.  
The results are presented in Figure 5. These firstly indicate that increasing the LIB lifetime by 10% leads to a reduction of the cumulated recoverable material by 15,072 tons (or 15%) compared to the base case. Secondly, increasing the share of LIBs entering 2 nd life causes a reduction of 9706 tons (10%). Thirdly, reducing the number of batteries entering recycling leads to a similar reduction of 9706 tones. Lastly, decreasing the production waste by 10% leads to a reduction of 52,452 tones (49%). Consequently, the sensitivity analysis reveals that the production waste and the battery lifetime have the highest impact on the cumulated amount of recovered material, followed by the recycling method, i.e., the share of hydrometallurgical recycling. Since the amount of production waste follows the growth in battery demand and dominates the LIB quantities directly entering recycling, the adjustment of this parameter has the highest impact on the availability of secondary materials. The analysis is carried out only for Co, given that it is the only material for which an intersection of secondary-material supply and demand can be expected.  
Based on the results, the sensitivity analysis shows how the availability of secondary materials from LIB recycling until 2035 is largely driven by the amounts of production waste. On the one hand, production waste is considered so-called \"post-industry waste\", which cannot be interpreted as an improvement in waste management and EoL operations for BEV. On the other hand, the results imply that improvements in LIB production process efficiency, which reduce the amount of waste occurring at the production stage, will reduce the amount of available secondary material. Consequently, using the amount of secondary LIB materials as a performance indicator in a CE does not incentivize measures for waste reduction in the first place. Therefore, automotive manufacturers and LIB producers additionally need to apply other metrics in order to measure and stir the material circularity of their products.