**Active materials development:**
**electrolyte:** An initial fluorinated solvent (ITER1), optimized on NMP-processed commercial LNMO cells, extended cycle life and performance but showed reduced gains on consortium materials, prompting reformulation. Adapting the chemistry to aqueous cathode processing yielded ITER2b, which was upscaled and cross-validated internally.
**Cathode:** LNMO development combined surface modification with electrochemical benchmarking; single-crystal, surface-treated LNMO was selected as the Iter2 candidate.
**Anode:** Silicon-graphite composites reached ~700 mAh g⁻¹ reversible capacity with ~90% initial coulombic efficiency. Adding carbon nanotubes improved conductivity and capacity retention, though densification challenges were identified. High-loading full cells revealed poor wettability and sluggish ionic transport, informing upscaling. Degradation studies comparing Iter1 vs. Iter2 electrolytes showed improved interphase stability and mitigation of rollover.
**Upscaling and 3D electrode engineering (multilayer coating, laser structuring)**
Pilot-line cathode processing with Iteration-1 LNMO succeeded. Multilayer coating was implemented by varying binder systems; aqueous LNMO reached 6 mAh cm⁻² at pilot scale. A similar multilayer approach for Si/C anodes was also demonstrated. Next, these multilayer electrodes will be validated with the high-performance electrolyte from WP2.
Laser structuring aimed to boost rate capability and transport. Work focused on process understanding—effects of pulse duration, mode, power, and binder—using Iteration-1 cathodes and anodes to identify optimal conditions. On cathodes, parameter studies reduced processing time while preserving electrochemical benefit; several structuring strategies were screened to maintain gains. Electrochemical evaluation is partially complete and ongoing. On anodes, structuring explored ablation behavior with the new Si/C material.
**Aeronautic module design**
A next-generation aerospace battery module was evaluated across four concepts—Pizza, Linear Module, Distributed Battery, and Active Swelling Management—against technical, environmental, thermal, and manufacturability criteria. The Linear Module was chosen for the final design due to its balance of performance, mass compliance, manufacturability, reusability, and eco-design fit. The architecture supports reconditioning and reuse of mechanical components to cut environmental impact, employing carbon-fiber composites and bio-based resins for high strength at low mass. Structural elements (housing, end plates, cell pack) were engineered for strength, integration, and thermal safety. Prototyping validated key assumptions; next iterations will increase rigidity and trim excess mass. Integrated features—thermal barriers, flexible sensing, quick-disconnect tabs—enhance safety and maintainability. The project now advances to final tooling, full-scale assembly, and validation testing, including thermal-runaway scenarios, toward certification readiness and industrial deployment.
**Cell Testing**
Performance and aging tests on Iter0 baseline cells at 25 °C and 0 °C used constant-current cycling up to 6C to assess capacity recovery and energy/power densities. Discharge-pulse series highlighted significant voltage drop from high internal resistance, limiting accessible capacity. Cycle-aging indicated a short current lifespan (~60 full-cycle equivalents). LIBS on aged cells showed more heterogeneous lithium distribution at 25 °C and pocket-like features consistent with wetting issues that trap lithium; these insights were fed back to improve Iter1/Iter2 cells.
**Recycling**
Two routes were advanced. The chemical separation route targets Li/Mn/Ni separation from LNMO: leaching and oxidative precipitation isolate Mn from Li/Ni, followed by continuous ion exchange to purify Ni to battery-grade (~99.9%) with >90% recovery of Mn and Ni. Lithium recovery requires prior removal from LNMO or an additional technology. The direct route regenerates LNMO and Si/Gr from scrap by delamination (chemical, thermal, or mechanical), LNMO relithiation, and Si/Gr regeneration; cost and environmental impacts are being quantified.
**Dissemination**
Four open-access papers have been published; one is provisionally accepted, and three are in preparation or planned—reflecting maturation of results. Communication highlighted researchers and beneficiaries via articles and short videos shared on LinkedIn and the project website. Public deliverables are accessible through CORDIS and the project site.
