Key Highlights

• A single full-format DSD LFP/LLZO pouch cell completed over 780 hours (65 cycles) of continuous electrochemical cycling at 0.2C, retaining approximately 75% of its initial capacity.

• The characteristic LFP voltage plateau at 3.4–3.5V was present in every cycle, and coulombic efficiency remained near 100% for the majority of the test, consistent with the cathode chemistry remaining active.

• Post-test inspection indicates the capacity fade is associated with the unoptimised cell build and reference components (liquid electrolyte and lithium-metal anode), rather than the DSD-deposited cathode.

• The company has not yet integrated its proprietary ASE solid-state electrolyte; this liquid-electrolyte baseline is early-stage laboratory work, not commercial manufacturing.

Critical Resources Limited (ASX:CRR) has reported the results of extended capacity retention testing of a full-format pouch cell built with a lithium iron phosphate/LLZO cathode matrix produced using the company's Dry Supersonic Deposition process, paired with a liquid reference electrolyte and a lithium-metal anode. The cell was cycled at 0.2C — a five-hour charge and five-hour discharge rate — with a one-hour rest following each charge and discharge step. Each full cycle took approximately 12 hours, and the 65-cycle programme represented approximately 780 hours of continuous electrochemical testing. The cell delivered an initial specific capacity of approximately 145 mAh g⁻¹ at 0.2C and retained approximately 75% of that capacity after 65 cycles.

Cathode Chemistry and Electrochemical Identity

The characteristic flat LFP voltage plateau at 3.4–3.5V was maintained in every one of the 65 cycles, which the company states is consistent with the cathode's Fe²⁺/Fe³⁺ redox chemistry remaining electrochemically active throughout the test period. Coulombic efficiency — a measure of how much lithium put into the cell during charge returns on discharge — remained near 100% for the vast majority of the test. The company noted that chemistry failures typically announce themselves rapidly through collapsing plateaus, distorted voltage signatures or sharply declining efficiency, and that none of these indicators occurred during the bulk of the test.

Capacity Fade Attributed to Cell Build, Not Cathode

The company has attributed the 25% capacity fade observed over 65 cycles primarily to the unoptimised, hand-assembled cell build and the two reference components — the liquid electrolyte and the lithium-metal anode — rather than the DSD-deposited cathode material itself. The fade mechanism is described as rising internal electrical resistance, which the company attributes to factors including electrolyte wetting across the large electrode format, stack pressure, cathode-to-anode alignment and layer-to-layer contact — all steps performed manually in this first-generation build. Post-test inspection by the CEPS research team at the South Dakota School of Mines & Technology indicated the DSD-deposited cathode appeared stable and intact on visual inspection while the lithium-metal anode showed heavy degradation, consistent with known behaviour of lithium metal in contact with liquid carbonate electrolytes. The company notes the post-test inspection was qualitative and not a completed failure analysis.

Context: Coin-Cell Performance and Full-Format Transition

Peer-reviewed research previously published for DSD-deposited LFP demonstrated approximately 85% capacity retention over 500 cycles at coin-cell scale — a result from a simpler format without the LLZO phase used in the pouch-cell matrix. The transition from coin-cell to full-format commonly reduces accessible capacity due to incomplete wetting, poor contact and inactive regions, and this cell was assembled by hand. The company noted that the initial capacity of approximately 145 mAh g⁻¹ was nonetheless consistent with the published coin-cell result, adjusted for the differences in test rate and composition. Cell assembly, formation protocols and electrode–electrolyte interfaces are described as optimisation levers with known engineering solutions, none of which has yet been applied to this build.

Next Steps and CSIRO Digital Twin Programme

The cell engineering optimisation phase is now underway, with defined focus areas including refinement of cell assembly, formation protocols, electrode–electrolyte interface protection and deposition parameter optimisation. In parallel, CSIRO has commenced Digital Twin modelling of the DSD deposition process at Lab22, Clayton, under a Kick-Start co-funded research collaboration. The company's next technical challenge is the replacement of the liquid electrolyte baseline with its proprietary Amorphous Solid-State Electrolyte, which has been benchmarked at 3.2 mS cm⁻¹ ionic conductivity. Integration of the ASE into the pouch-cell platform is described as the next programmatic step. Independent third-party electrochemical testing of an optimised baseline cell is also planned.

Conclusion

Critical Resources (ASX:CRR) has completed a month of continuous cycling in a first-generation, hand-assembled, full-format DSD pouch cell, with the LFP cathode chemistry active in every cycle and approximately 75% capacity retention over 65 cycles. The result is characterised by the company as an engineering baseline rather than a finished performance figure, with capacity fade attributed to the cell build and reference components rather than the DSD cathode material. Optimisation work is underway, with integration of the proprietary ASE solid-state electrolyte as the next technical milestone. The programme remains at an early-stage laboratory phase.