Novel High-Capacity Composite Anodes for the Upcycling of Spent Graphite from End-of-Life Lithium-Ion Batteries (Phase II)

In terms of energy storage, lithium-ion batteries are the clear solution of choice for applications ranging from consumer electronics to electric vehicles and they will remain so for decades to come. Increasing demand for batteries is a concern because there are not enough raw materials available to support this projected growth. Further, battery-grade graphite, a key component of lithium-ion batteries, is almost exclusively supplied from foreign sources. The Vehicle Technologies Office has taken special interest in technologies that focus on mitigating global supply risk by establishing work based on three foundational pieces: (1) diversifying supply chains, (2) developing material and technology substitutes, and (3) promoting recycling, reuse, and efficiency. The proposed work addresses all three of these goals by upcycling low-value recycled graphite obtained from spent lithium-ion batteries into high-capacity, high value anode materials for use in new batteries. Though recycling of batteries is currently performed by several companies, none of their recycling methods is optimized to provide graphite suitable for conversion directly to electrodes, due to the cost of removing organic and inorganic impurities. The innovation developed in Phase I is a process to utilize impure recycled graphite to create a new high-capacity anode material by applying a proprietary, low-cost, inorganic, resin-based technology to create conductive ceramics. Previous work by the proponent has shown that polymer derived ceramics, which are the result of inert gas pyrolysis of ceramic-forming polymers, can be used to encapsulate impurities and inhibit their deleterious effects on graphite performance. In Phase I, previously obtained results were used as a foundation to develop and demonstrate the process for producing high-performance graphite for use in battery anodes from recycled materials obtained from multiple different sources. Electrochemical performance of the developed anode composites was characterized, with a focus on specific capacity and first-cycle efficiency in cells up to 225 mAh. Phase II will result in fabrication and testing of larger cells (up to 2 Ah) using recycled graphite composite anodes to demonstrate commercial viability of the technology. Further optimization of electrochemical performance metrics will be performed to identify the best possible cost vs. performance formulations. Lifecycle and techno-economic analyses will be performed in concert with market partners to establish realistic pathways to commercialization and profitability for the technology. The primary benefit of this work will be the ability to use recycled graphite (designated as a critical mineral), which until now, has not been deemed economically viable due to low purity and rejuvenation cost post-recycling. The concomitant reduction in dependence on foreign sources of a critical material is of interest for national security and supply chain issues. Further, use of recycled graphite through this process promises to require less energy and simplified manufacturing scale-up compared to other approaches. Beyond Phase II, the technology can be applied to larger batteries with the eventual goal of supporting recycling and reuse of materials from and for large market consumers such as electric vehicles.