▎ 摘　　要

NOVELTY - Preparing a hydrogel, involves forming a pre-gel comprising polymer and metal salt particles, unidirectionally shrinking and dehydrating the pre-gel and impregnating the unidirectionally shrunk and dehydrated pre-gel with an ion solution-I to crosslink and rehydrate the unidirectionally shrunk and dehydrated pre-gel to produce the hydrogel. USE - Method for preparing a hydrogel that is utilized in energy storage device (all claimed) such as all-solid-state lithium-ion batteries and supercapacitors. ADVANTAGE - The method is simple and provides eco-friendly hydrogel with excellent mechanical properties such as rigidity and fracture toughness increased lithium-ion conductivity and superior heat dissipation ability, thus preventing internal short circuit and overheating and providing energy storage device with stable operation. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for the hydrogel, which is prepared by the method.