Systems and methods for lightning strike materials are disclosed. The material may include a carbon fiber tow (110). Carbon nanotubes may be grown on carbon fibers (112;122) within the carbon fiber tow (110). The carbon nanotubes may cause the carbon fibers (112;122) to separate, decreasing a carbon tow fiber volume fraction of the tow (110). The growth of the carbon nanotubes may be controlled to select a tow fiber volume fraction of the tow (110). The lightning strike material may transmit electricity to decrease damage to the composite structure in case of a lightning strike.