Sustainable and Flexible Energy Storage Devices: A Review

In recent years, the growing demand for increasingly advanced wearable electronic gadgets has been commonly observed. Modern society is constantly expecting a noticeable development in terms of smart functions, long-term stability, and long-time outdoor operation of portable devices. Excellent flexibility, lightweight nature, and environmental friendliness are no less important aspects of the choice of mobile electronics. Naturally, electronic devices need efficient portable power sources (batteries and supercapacitors) that meet the above-mentioned requirements. However, most of these power sources use plastic substrates for their manufacture. Hence, this review is focused on research attempts to shift energy storage materials toward sustainable and flexible components. We would like to introduce recent scientific achievements in the application of noncellulosic polysaccharides for flexible electrochemical energy storage devices as constituents in composite materials for both batteries and supercapacitors. In this review, we will summarize the introduction of biopolymers for portable power sources as components to provide sustainable as well as flexible substrates, a scaffold of current collectors, electrode binders, gel electrolyte matrices, separators, or binding scaffolds for whole devices.