▎ 摘　　要

Graphene oxide (GO) sheets were synthesized via a modified Hummer's method. Subsequently, annualring shaped graphene hydrogel was formed through alkali-inducing hydrothermal process. The lyophilized GO hydrogel was tailored to a cylindrical emitter and demonstrated good field emission performance: maximum current density reached 2.32 mA/cm(2), field enhanced factor of 1969 and turn-on electric field at 2.41 V/mu m, accompanied with excellent stability. Moreover, the emitter also exhibited superior mechanical properties, such as ultra-light, flexibility and free-standing. These results suggest that the resultant with unique structure has a potential to be utilized as a high-performance field emitter. (C) 2017 Elsevier B.V. All rights reserved.