A ringset is configured to be arranged on a piston for sealing a gas in a high-pressure region of a cylinder in the absence of oil or other liquid lubricant. The ringset includes one or more rings made from a high-strength material as a sealing element. The ringset also includes a solid lubricant applicator configured to provide lubrication between the one or more rings and a bore of the cylinder. For example, the ring can support pressure loads from high-pressure gas without breaking, while the applicator need not act as a seal. As the piston reciprocates in the bore, the applicator slides against the bore and applies solid lubricant material to the bore, resulting in a solid lubricant film on the bore against which the sealing element may slide. The applicator includes a material such as a graphite, a polymer, or other suitable solid lubricant.