Two electrode designs are described that are capable of producing high output energy densities from pulsed atmospheric pressure CO2-N2-He lasers. In both cases a uniform volumetric excitation is obtained by the use of an auxiliary discharge. The first system uses a mesh cathode and has produced 4.8 J from an excited volume of 800 cm3(6 J.1-1). The second system uses a solid cathode and has produced 2 J from an excited volume of 110 cm3(18 J.1-1). Results of a parametric study of the solid cathode system are given. The output pulse energy, peak power, and pulse shape have been studied as functions of the energy-storage capacitor value, charging voltage, and gas composition. Partial self-mode-locking and the effect of single-mode operation on the pulsewidth have been observed.