From NMC to NMC—Towards Circular Economy

Since the introduction of lithium-ion batteries, we have entered the "portable era." Starting January 1^st, 2035, a European Parliament regulation will require all newly manufactured vehicles to be fully electric, aiming for a 100% reduction in CO₂ emissions from transportation. However, efficient battery recycling methods are essential for electric vehicles to be truly sustainable as the accumulation of battery waste poses long-term environmental risks. The battery industry faces numerous challenges, including rising material costs and geopolitical concerns related to ore mining and extracting critical raw materials. Efficient resource management has become a top priority for the European Union, driven by EU regulations. Recent studies highlight growing research into recycling and reusing materials from lithium-ion batteries. With the increasing number of lithium-ion cells powering electric vehicles and electronics, managing waste batteries has become an urgent issue. Current lithium-ion battery recycling mainly focuses on recovering valuable metals such as cobalt and nickel, with lithium often lost in pyrometallurgical processes. However, cathode materials can be fully recovered and reused in new battery applications. According to the latest EU directive on batteries, at least 35% of lithium and 90% of cobalt, nickel, and manganese must be recovered from waste lithium-ion cells. From 2030, new batteries must contain at least 6% recycled lithium. While large-scale processing remains economically challenging, global supply shifts, geopolitical events, technological advances, and stricter environmental regulations push stakeholders to view battery recycling as financially viable and sustainable. Recycling processes must achieve high efficiency and minimize environmental impact, with specific optimization required for each electrode material.
This study focuses on recycling lithiated nickel-manganese-cobalt oxide (LiNi_0.6Mn_0.2Co_0.2O₂), or NMC622, chosen for its high energy and power density, strong resistance to charge/discharge cycles, and favorable economic and environmental characteristics, including reduced but still significant cobalt content. NMC622 was recycled through steps including hydrometallurgical recovery of transition metal ions as hydroxides, though efficient lithium recovery remains a critical challenge. The recovered lithium and transition metals were used to resynthesize electrode materials. Crystallographic analysis confirmed the structural integrity and purity of the recycled materials. A series of NMC622 electrode materials with 0% to 100% recycled lithium were structurally and electrochemically characterized and compared to the original. Results showed that recycled materials can perform comparably to those made from virgin materials. However, achieving battery-grade purity remains a challenge, as post-recycling impurities affect the durability and stability of the materials during charge/discharge cycles. This research introduces a novel, streamlined method for recycling NMC, a key battery waste material. The eco-friendly technology efficiently extracts lithium from NMC powders, which can be re-lithiated or fully recycled for reuse as active electrode material. The extracted lithium can be converted into hydroxide or carbonate and used as a precursor in synthesizing new or recycled NMC materials. The performance and structural properties of these resynthesized materials will be discussed.

This research has been supported by the Initiative Excellence Research University Action I.3.4 The Circular Economy - Energy Storage.