The emerging field of direct recycling for spent Li-ion batteries offers significant advantages, such as reduced energy expenses and minimized secondary pollution, when compared to traditional pyrometallurgical and hydrometallurgical methods. This is due to its direct utilization of the spent cathodes as raw materials. However, efficient harvesting of spent cathode particles remains a challenge. To address this issue, this technical brief is the first to incorporate resonant acoustic vibration technology (RAV) as an efficient method for stripping cathode powders from spent Li-ion batteries. Our findings indicate that RAV-based techniques can achieve a stripping efficiency of up to 92%. A comparative analysis with conventional stripping methods, such as magnetic stirring, sonication, and curling–uncurling, reveals that RAV coupled with heat treatment provides unparalleled scalability and efficiency, eliminating the need for post-processing. Furthermore, the resulting cathode powders retain their original polycrystalline particle structures, with no impurities, such as carbon black or small aluminum fragments detected. These findings highlight the promise of RAV technology for large-scale recovery of electrode powders and its potential role in direct recycling of spent Li-ion batteries.

In additively manufactured (AM) Ti-6Al-4V, the role of martensitic α′ in governing brittleness versus toughness remains debated, largely because complex thermal histories and other intertwined physical factors complicate interpretation. To isolate and clarify the intrinsic effect of cooling rate, we employed a Gleeble thermal simulator, which enables precisely controllable cooling rates while simultaneously achieving ultra-fast quenching comparable to AM (up to ~7000 °C/s). By varying the cooling rate only, three distinct microstructures were obtained: α/β, α_m/α′, and fully α′. Compression tests revealed that the ultra-fast-cooled fully martensitic Ti-6Al-4V attained both higher strength and larger fracture strain, with densely distributed elongated dimples indicative of ductile failure. Three-dimensional microstructures reconstructed from microscopy, analyzed using an EVP-FFT crystal plasticity model, demonstrated that refined α′ laths and abundant high-angle boundaries promote more homogeneous strain partitioning and reduce stress triaxiality, thereby delaying fracture. These results provide potential evidence that extreme-rate martensitic transformation can overcome the conventional strength–ductility trade-off in Ti-6Al-4V, offering a new paradigm for processing titanium alloys and AM components with superior performance.