Developing porous self-supporting electrodes with excellent conductivity, good mechanical properties, and high electrochemical activity is crucial for constructing electrode materials with lightweight, ultra-thin, flexible, and high capacitance performance. In this work, we prepared a cellulose nanofibers (CNFs)/carbon nanotubes (CNTs)/vinasse activated carbon (VAC) (CCV) composite material with a multi-layer hierarchical conductive structure through simple vacuum filtration and freeze-drying. In this composite material, the self-assembly of CNF provides the main skeleton structure of a multi-layer hierarchical structure. CNT provides a fast path for the rapid transfer of electrons and is beneficial for the loss of electromagnetic waves. VAC provides sufficient double layer performance. The synergistic effect of the above three endows CCV composite materials with excellent energy storage performance and electromagnetic interference (EMI) shielding performance. In addition, we endowed the CCV composite with a certain shape and performance by introducing a vitrimer polymer with a dynamic cross-linked network structure. In summary, thanks to the synergistic effect of various components in the multi-layer hierarchical structure, CCV composite materials exhibit excellent integration performance, especially stable energy storage performance and EMI shielding performance. These significant properties make CCV composite materials have great application prospects in the fields of energy storage and intelligent EMI shielding.

Due to their rich and adjustable porous network structure, paper-based functional materials have become a research hotspot in the field of energy storage. However, reasonably designing and making full use of the rich pore structure of paper-based materials to improve the electrochemical performance of paper-based energy storage devices still faces many challenges. Herein, we propose a structure engineering technique to develop a conductive integrated gradient porous paper-based (CIGPP) supercapacitor, and the kinetics process for the influence of gradient holes on the electrochemical performance of the CIGPP is investigated through experimental tests and COMSOL simulations. All results indicate that the gradient holes endow the CIGPP with an enhanced electrochemical performance. Specifically, the CIGPP shows a significant improvement in the specific capacitance, displays rich frequency response characteristics for electrolyte ions, and exhibits a good rate performance. Also, the CIGPP supercapacitor exhibits a low self-discharge and maintains a stable electrochemical performance in different electrolyte environments because of gradient holes. More importantly, when the CIGPP is used as a substrate to fabricate a CIGPP-PANI hybrid, it still maintains good electrochemical properties. In addition, the CIGPP supercapacitor also shows excellent stability and sensitivity for monitoring human motion and deaf-mute voicing, showing potential application prospects. This study provides a reference and feasible way for the design of structure-engineered integrated paper-based energy storage devices with outstanding comprehensive electrochemical performance.

Recent research efforts in the field of electromagnetic interference shielding (EMI) materials have focused on biomass as a green and sustainable resource. More specifically, wood and cellulose nano fiber (CNF) have many advantages, some of which include lightweight, porosity, widespread availability, low cost, and easy processing. These favorable properties have led researchers to consider these types of biomass as an EMI shielding material with great potential. At present, while many excellent published works in EMI shielding materials have investigated wood and CNF, this research area is still new, compared with non-biomass EMI shielding materials. More specifically, there is still a lack of in-depth research and summary on the preparation process, pore structure regulation, component optimization, and other factors affecting the EMI shielding of wood and CNF based EMI shielding materials. Thus, this review paper presents a comprehensive summary of recent research on wood and CNF based EMI shielding materials in recent three years in terms of the preparation methods, material structure design, component synergy, and EMI mechanism, and a forward future perspective for existing problems, challenges, and development trend. The ultimate goal is to provide a comprehensive and informative reference for the further development and exploration of biomass EMI shielding materials.