Circular economy strategies for mitigating metals shortages in electric vehicle batteries under China's carbon-neutral target

Concerns over supply risks of critical metals used in electric vehicle (EV) batteries are frequently underscored as impediments to the widespread development of EVs. With the progress to achieve carbon neutrality by 2060 for China, projecting the critical metals demand for EV batteries and formulating strategies, especially circular economy strategies, to mitigate the risks of demand-supply imbalance in response to potential obstacles are necessary. However, the development scale of EVs in the transport sector to achieve China's carbon neutrality is unclear, and it remains uncertain to what extent circular economy strategies might contribute to the reduction of primary raw materials extraction. Consequently, we explore the future quantity of EVs in China required to achieve carbon neutrality and quantify the primary supply security levels of critical metals with the effort of battery cascade utilization, technology substitutions, recycling efficiency improvement, and novel business models, by integrating dynamic material flow analysis and national energy technology model. This study reveals that although 18%-30% of lithium and 20%-41% of cobalt, nickel, and manganese can be supplied to EVs through the reuse and recycling of end-of-life batteries, sustainable circular economy strategies alone are insufficient to obviate critical metals shortages for China's EV development. However, the supplementary capacity offered by second-life EV batteries, which refers to the use of batteries after they have reached the end of their first intended life, may prove adequate for China's prospective novel energy storage applications. The cumulative primary demand for lithium, cobalt, and nickel from 2021 to 2060 would reach 5-7 times, 23-114 times, and 4-19 times the corresponding mineral reserves in China. Substantial reduction of metals supply risks apart from lithium can be achieved by the cobalt-free battery technology developments combined with efficient recycling systems, where secondary supply can satisfy the demand as early as 2054.

Novel Indicators for the Quantification of Resilience in Critical Material Supply Chains, with a 2010 Rare Earth Crisis Case Study

We introduce several new resilience metrics for quantifying the resilience of critical material supply chains to disruptions and validate these metrics using the 2010 rare earth element (REE) crisis as a case study. Our method is a novel application of Event Sequence Analysis, supplemented with interviews of actors across the entire supply chain. We discuss resilience mechanisms in quantitative terms-time lags, response speeds, and maximum magnitudes-and in light of cultural differences between Japanese and European corporate practice. This quantification is crucial if resilience is ever to be taken into account in criticality assessments and a step toward determining supply and demand elasticities in the REE supply chain. We find that the REE system showed resilience mainly through substitution and increased non-Chinese primary production, with a distinct role for stockpiling. Overall, annual substitution rates reached 10% of total demand. Non-Chinese primary production ramped up at a speed of 4% of total market volume per year. The compound effect of these mechanisms was that recovery from the 2010 disruption took two years. The supply disruption did not nudge a system toward an appreciable degree of recycling. This finding has important implications for the circular economy concept, indicating that quite a long period of sustained material constraints will be necessary for a production-consumption system to naturally evolve toward a circular configuration.

Macroscopic Evidence for the Hibernating Behavior of Materials Stock

Hibernating stock is defined as material stock that is no longer used, but is not yet recovered. Although hibernating stock plays a role in materials recoverability, its contribution to the overall material cycle is not clearly understood. Therefore, an analysis of the time-series potential generation of steel scrap in Japan was performed and compared against the actual recovery, proving that the steel scrap recovered each year exceeds the annual generation potential and providing the first macroscopic evidence of hibernating stock recovery. These results indicate that hibernation behavior should be considered when evaluating materials recoverability. The particular characteristics of hibernating stock were also identified. These materials tend to be located far from scrap yards and/or have low bulk density, while also minimally obstructing new activity. In fact, hibernating materials are typically only recovered when they obstruct new activity. Hence, in order to increase steel recoverability, the recovery cost must be reduced. The end-of-life recycling rates (EoL-RRs) were also evaluated, and were found to exhibit a significant change over time. Consequently, the annual EoL-RR cannot be considered as a representative value, and a value for the EoL-RR(s) of relevant year(s) that has been evaluated over the entire period should be used instead.

Framework for resilience in material supply chains, with a case study from the 2010 Rare Earth Crisis

In 2010, Chinese export restrictions caused the price of the rare earth element neodymium to increase by a factor of 10, only to return to almost normal levels in the following months. This despite the fact that the restrictions were not lifted. The significant price peak shows that this material supply chain was only weakly resistant to a major supply disruption. However, the fact that prices rapidly returned to lower levels implies a certain resilience. With the help of a novel approach, based on resilience theory combined with a material flow analysis (MFA) based representation of the neodymium magnet (NdFeB) supply chain, we show that supply chain resilience is composed of various mechanisms, including (a) resistance, (b) rapidity, and (c) flexibility, that originate from different parts of the supply chain. We make recommendations to improve the capacity of the NdFeB system to deal with future disruptions and discuss potential generalities for the resilience of other material supply chains.

Outlook of the world steel cycle based on the stock and flow dynamics

We present a comprehensive analysis of steel use in the future compiled using dynamic material flow analysis (MFA). A dynamic MFA for 42 countries depicted the global in-use stock and flow up to the end of 2005. On the basis of the transition of steel stock for 2005, the growth of future steel stock was then estimated considering the economic growth for every country. Future steel demand was estimated using dynamic analysis under the new concept of "stocks drive flows". The significant results follow. World steel stock reached 12.7 billion t in 2005, and has doubled in the last 25 years. The world stock in 2005 mainly consisted of construction (60%) and vehicles (10%). Stock in these end uses will reach 55 billion t in 2050, driven by a 10-fold increase in Asia. Steel demand will reach 1.8 billion t in 2025, then slightly decrease, and rise again by replacement of buildings. The forecast of demand clearly represents the industrial shift; at first the increase is dominated by construction, and then, after 2025, demand for construction decreases and demand for vehicles increases instead. This study thus provides the dynamic mechanism of steel stock and flow toward the future, which contributes to the design of sustainable steel use.