The industry optimizes in one dimension (ΔH) when the thermodynamics permits two-dimensional optimization in (ΔH, ΔS) space
- Every DAC sorbent review plots binding enthalpy vs. capacity.
- No one plots entropy change.
- Yet the Gibbs equation permits achieving the same binding free energy through entropy-dominated materials—where TΔS_release assists regeneration.
- This is why phase-change materials, cooperative binding, and conformational transitions represent genuinely unexplored territory.
- Multiple chemistries already achieve <60 kJ/mol—the challenge is translating proven thermodynamics to DAC conditions, not discovering new physics.
If you prioritize speed to validation and can accept humidity constraints, pursue Benfield revival. If you need proven commercial pathway with partnership opportunity, engage Svante on CALF-20. If you're optimizing for long-term breakthrough, fund entropy engineering research.
Promoted Potassium Carbonate on Ceramic Honeycomb (Benfield Revival)
50 kJ/mol thermodynamics proven at industrial scale; amino acid promoters may solve kinetics; 6-8 week validation
Entropy-Engineered Phase-Change Ionic Liquid
TΔS contribution could reduce effective regeneration to 30-40 kJ/mol; materials discovery required; 3-5 years
- If this were my project, I'd start with the Benfield validation test next week—it's the highest expected value move.
- Order the honeycomb samples, prepare the impregnation, and get a breakthrough curve at 400 ppm.
- Six weeks and $100K to know if 50 kJ/mol thermodynamics translate to DAC conditions.
- If kinetics work, you've found the fastest path to your target using chemistry that's been proven at industrial scale for 50 years.
- In parallel, I'd have a conversation with Svante about CALF-20 partnership.
- They've already proven 45 kJ/mol—below your target.
- If their manufacturing roadmap is credible and their cycle stability data is solid, this might be the path of least resistance.
- Don't reinvent what's already commercializing.
- The entropy engineering concepts (IL phase change, LC hosts) I'd fund as academic partnerships—$200-500K to screen the compositional space over 18-24 months.
- Low probability of immediate success, but if someone finds a material that works, it's a paradigm shift.
- Worth the asymmetric bet.
- But I wouldn't let it delay the near-term paths.
- The one thing I'd want to understand better before committing serious capital: what's your waste heat situation? If you have 80-120°C waste heat at no marginal cost, even 70 kJ/mol amines might work economically.
- The 60 kJ/mol target matters most if you're paying for heat.
- If heat is free, focus on cycle stability and capital cost instead.