Current collectors set the electrical backbone of every cell — they govern contact resistance, corrosion stability, and how much active material you can actually load. This collection covers the metallic foils, foams, felts, meshes, and carbon-based substrates used as anode and cathode current collectors across lithium-ion, aqueous, flow, fuel-cell, and electrolyzer systems. Choices here propagate downstream: a poorly matched collector causes voltage decay, dendrite nucleation, or anodic dissolution that no electrolyte tweak can rescue.
2D foils for conventional electrodes
Standard cathode and anode substrates start as smooth metal foils, with surface engineering to address specific failure modes. Carbon-coated aluminum foils (including temperature-sensitive variants tuned for dry-electrode processing) reduce interfacial resistance and prevent delamination during calendering and cycling. Microporous aluminum introduces through-holes for bidirectional ion transport and prelithiation pathways. For chemistries that attack aluminum — concentrated imide salts, high-voltage holds, or aqueous electrolytes — tantalum foil offers exceptional corrosion resistance, and carbon-coated stainless steel provides a cost-effective route in aqueous cells where bare SS316L would passivate or pit.
3D porous architectures
Foams, felts, and woven meshes step beyond planar geometry to host more active material, accommodate volume change, and suppress dendrites. Copper foam serves Li-metal and high-power anodes by spreading current density across an interconnected ligament network. Titanium foam targets zinc-ion, aluminum-ion, and aqueous-Li systems where corrosion resistance and gas suppression matter most. Nickel felt is the workhorse for redox-flow electrodes and high-temperature alkaline cells, while stainless-steel mesh rolls provide a tunable open-area substrate for thick electrodes and lithium-metal hosts. Self-standing MWCNT electrodes go one step further, eliminating the metal collector entirely and acting as both conductor and active scaffold for supercapacitors and binder-free batteries.
Gas-phase devices
For electrolyzers and fuel cells, current collection is inseparable from gas diffusion. Hydrophobic carbon papers with integrated microporous and PTFE layers bridge the bipolar plate to the catalyst layer, balancing electronic conduction with water management. Woven silver mesh handles cathode current collection in intermediate-temperature SOFC and flow-through configurations where conductivity must survive oxidizing, high-temperature service.
If you are building a Li-ion or Na-ion coin cell, start with the aluminum and copper foils; for Li-metal, Zn-ion, or aqueous work, move to the 3D foams and meshes; for membrane-electrode assemblies, see the carbon paper and silver mesh options.
