Cellulose Nanomaterials Based Flexible Electrodes for All-Solid-State Supercapacitors

In recent years, flexible all-solid-state supercapacitors have been widely used as the energy storage devices for various smart and wearable electronic devices. However, the design and fabrication of high-performance flexible supercapacitor electrodes is still challenging since most of the active materials used for supercapacitor electrodes lack the ability to form flexible and mechanically stable structures. Recently, cellulose nanomaterials (mainly include cellulose nanocrystals and cellulose nanofibrils) have gained extensive interests due to their large specific surface areas, versatile surface chemistry, high mechanical strength, and the ability to form mechanically stable structures (e.g., films, aerogels). These days, the design of flexible supercapacitor electrodes by combining cellulose nanomaterials with different active materials gradually attracted the attention of scholars. The main objective of this review is to give an overview of recent developments in the preparation of cellulose nanomaterials based flexible all-solid-state supercapacitor electrodes. The fabrication approach, structure characterization, and electrochemical performance of the invented cellulose nanomaterials based flexible supercapacitor are elaborated. Also, the current challenges and future outlook for the design and fabrication of cellulose nanomaterials based flexible all-solid-state supercapacitor are proposed.