Electrode additives decide whether a fuel-cell or electrolyzer electrode actually works at the rated current density — they set electronic percolation through the catalyst layer, manage water in the gas-diffusion layer, and control mechanical integrity during calendaring and stack assembly. This collection groups the powders, slurries, and porous supports that researchers blend into MEAs, GDLs, and adjacent supercapacitor electrodes built on the same fabrication platforms.
Hydrophobicity & water management
PTFE nanopowder is the workhorse hydrophobic agent for gas-diffusion layers and microporous layers. Coating carbon fibers with submicron PTFE raises the water contact angle so liquid product water drains while H2, O2, or CO2 reach the catalyst sites. Without it, GDLs flood at high current density and the limiting current collapses.
Conductive networks
Carbon nanotubes form the 1D electron-transport backbone of catalyst layers and thick supercapacitor electrodes. Covalently functionalized single-wall nanotubes disperse into a 3D percolating network at very low loadings, while multi-wall nanotube slurries trade some conductivity for cost and easier processing in high-loading coatings. Both reduce ohmic drop and reinforce the layer against cracking during calendaring.
Porous carbon supports
Hierarchical, mesoporous, and disordered porous carbons act as catalyst supports and as primary EDLC electrodes. The relevant axes are pore architecture (macro for ion reservoirs, meso for transport, micro for double-layer storage), specific surface area, pore volume (high-pore-volume carbons load pseudocapacitive or electrocatalytic guests without clogging), and surface chemistry. Nitrogen-doped carbons add pyridinic and pyrrolic sites that contribute pseudocapacitance and anchor metal catalysts. Coconut-shell-derived activated carbons remain the reference EDLC material for their balanced micropore distribution matched to TEA+ / BF4- electrolytes.
Functional & sacrificial additives
Lithium squarate (Li2C4O4) is an organic sacrificial pre-lithiation salt — it decomposes on the first charge to CO/CO2 and Li+ with effectively no dead weight, compensating first-cycle losses. Non-fluorine plasticizers lower the binder Tg so dense electrodes stay ductile through calendaring without cracking or delaminating.
If you are building MEA catalyst layers or GDLs, start with the PTFE and CNT additives; if you are building EDLC or hybrid-capacitor electrodes on the same line, see Supercapacitor. For binders and ionomers, see Binders; for the wider fuel-cell and electrolyzer stack, see Electrolyzers & Fuel Cells.
