In the present paper, the hybrid storage materials have been used to improve the solar still productivity. The hybrid storage materials represent a mixture of paraffin wax and graphite nanoparticles, the objective of using the present hybrid storage materials improve the thermal properties of storage materials as well as improve the still productivity. The conventional still and the solar still with a hybrid storage material was constructed and tested to investigate the improvement in a distillate production. Also, the effects of graphite nanoparticles mass concentrations in hybrid storage materials on the performance of solar still have been investigated. The experimental results showed that the accumulated distillate production of a solar still with hybrid storage materials is more than that of conventional basin still. The accumulated distillate production of solar still with hybrid storage materials reached to 7.123, 7.475, 7.937, 8.249, and 8.521/m(2) day for 0.0%, 5%, 10%, 15%, and 20% graphite nanoparticles mass concentrations, respectively. While the distillate production reached to 4.381/m2 day for the conventional still. The percentage improvement in a water production was recorded 62.62%, 70.66%, 81.21%, 88.33%, and 94.52% for 0.0%, 5%, 10%, 15%, and 20% graphite nanoparticles mass concentrations, respectively, as compared to the conventional still. Also, the daily efficiency of solar still with hybrid storage materials was about 51.41%, 54.94%, 59.2%, 62.38%, and 65.13% for 0.0%, 5%, 10%, 15%, and 20% graphite nano particles mass concentrations, respectively, but for the conventional still the daily efficiency was about 32.257%. (C) 2018 Elsevier Ltd. All rights reserved.