Flexible electrochemical energy storage device and preparation method thereof

The invention discloses a flexible electrochemical energy storage device and a preparation method thereof. The preparation method comprises the following steps: (1) preparing a transition metal compound doped lignin/rubber composite material elastic basement membrane by adopting an emulsion blending method or a mechanical blending method; and 2) pre-stretching the elastic substrate film obtained in the step 1), then carrying out laser direct writing in-situ carbonization, and recovering pre-stretching after laser direct writing to prepare the transition metal compound doped lignin/rubber composite material based flexible electrochemical energy storage electrode, and 3) packaging the energy storage electrode obtained in the step 2) to obtain the flexible electrochemical energy storage device. The preparation method is simple, the raw materials are cheap and easy to obtain, and the obtained energy storage device has high mechanical performance, high elasticity, high conductivity and good tensile cycling stabili