Brunauer-Emmett-Teller (BET)
BET surface area analysis measures the specific surface area of powders and porous materials by fitting nitrogen or argon adsorption isotherms to the Brunauer-Emmett-Teller theory, yielding total surface area per gram and pore-size distribution. As a hard skill it requires correct sample degassing to remove moisture and adsorbed gases, selection of appropriate relative pressure ranges for the linear BET fit, and interpretation of isotherm shape to infer pore structure. Battery researchers apply BET to characterize cathode powders, anode carbons, and separator materials, where surface area strongly influences capacity, rate performance, and electrolyte uptake.
