Four ways to make a lithium metal anode, compared
A review in EcoEnergy (Wiley) this month did something the field needed: it compared the four routes to a lithium metal anode on the same axes, rather than one at a time.
The comparison
| Extrusion | Molten infusion | Electroplating | Vapour deposition | |
|---|---|---|---|---|
| Thickness | 20–100 µm | 10–100 µm | 1–50 µm | nm–10 µm |
| Purity | ≥ 99.9% | ≥ 99.9% | ≥ 99.9% | ≥ 99.99% |
| Surface roughness | moderate | host-dependent | controllable | excellent |
| Throughput | 10–50 m/min | < 10 m/min | m/min scale | low–medium |
Extrusion and molten infusion win on cost and throughput but struggle below 10 µm. Electroplating controls thickness well but inherits the purity of its bath. Vapour deposition gives the highest purity and the flattest films, at the cost of rate — which is precisely the trade the review identifies as the one worth engineering against.
The review also notes hybrid routes: a vapour-deposited seed layer followed by electroplating gets a clean nucleation surface and a fast build, and the industry targets it cites are 20–30 µm for 350 Wh/kg cells and 10–15 µm for 500 Wh/kg, at surface roughness below 0.5–1.0 µm.
Scale-up, this month
- Ganfeng Lithium began small-batch solid-state production at 500 Wh/kg with over 1,100 cycles demonstrated at the 400 Wh/kg level, aimed at eVTOL.
- Basquevolt launched BQV400L: 402 Wh/kg, 27 Ah, 8.9C pulse, polymer electrolyte, designed as a drop-in for existing European gigafactory lines.
- Pure Lithium brought a 500 MWh all-solid-state line to full operation, claiming 6,000–8,000 cycles on 50 Ah cells.
- QuantumScape added JB Straubel to its strategic advisory board and formalised expansion beyond EVs into AI data centres and aerospace.
- Solid Power expanded sulfide electrolyte output from 30 to 75 MT/yr.
- JACS (CAS Institute of Metal Research) reported a PVDF-based solid-state Li-metal electrolyte reaching 451.5 Wh/kg in Ah-class pouch cells, with 700 cycles at 20C and 81.9% retention, passing nail penetration.
The anode-free window
Anode-free cells remove the anode active material entirely — lithium plates directly onto the current collector on first charge. Projections put the solid-state market at $33.3B by 2033 on a 36.4% CAGR, with over 900 Wh/L achievable and commercialisation expected from 2027.
The obstacles are honest ones: volumetric expansion, dendrite growth, and plating efficiency over hundreds of cycles. Current solid-state cells cost three to five times a lithium-ion equivalent, with a 1.5× target by 2030.
First applications are not cars. They are humanoid robots, urban air mobility, defence and drones — places where weight is worth more than cost. Premium EVs follow.
Where this points
Two commercialisation paths have split cleanly: drop-in cells for existing lines, and capital-light materials supply. Either way, the step that decides whether an anode-free cell survives its first charge is how uniformly lithium nucleates on the collector.