Realization of high-purity 1T-MoS2 by hydrothermal synthesis through synergistic effect of nitric acid and ethanol for supercapacitors

•Ambient stable 1T-MoS2 with high purity can be synthesized in hydrothermal processing under the synergistic effect of nitric acid and ethanol.•The electrodes of MoS2(Synergism) show outstanding electrochemical performance.•The all-solid-state flexible asymmetric supercapacitors devices achieve the high energy density and cycle stability.•The results provide a facile route to realize phase engineering of transition metal dichalcogenides through synergistic effects.