Nanoscale Ion Regulation in Wood‐Based Structures and Their Device Applications

Abstract

Ion transport and regulation are fundamental processes for various devices and applications related to energy storage and conversion, environmental remediation, sensing, ionotronics, and biotechnology. Wood‐based materials, fabricated by top‐down or bottom‐up approaches, possess a unique hierarchically porous fibrous structure that offers an appealing material platform for multiscale ion regulation. The ion transport behavior in these materials can be regulated through structural and compositional engineering from the macroscale down to the nanoscale, imparting wood‐based materials with multiple functions for a range of emerging applications. A fundamental understanding of ion transport behavior in wood‐based structures enhances the capability to design high‐performance ion‐regulating devices and promotes the utilization of sustainable wood materials. Combining this unique ion regulation capability with the renewable and cost‐effective raw materials available, wood and its derivatives are the natural choice of materials toward sustainability.

Highly Flexible and Broad-Range Mechanically Tunable All-Wood Hydrogels with Nanoscale Channels via the Hofmeister Effect for Human Motion Monitoring

“…As previously reported on wood-hydrogel conductors, the cellulose nanofibers commonly act as nanochannels for ion transport [10,25,30,50]. The strain sensitivity of the allwood hydrogel is tested by calculating the gauge factor (GF, high value means higher sensitivity) of relative resistance variation ((R-R 0 )/R 0 ) with strain.…”

“…Recently, a composite hydrogel containing a natural micro-/nanofiber reinforcer was explored, which significantly improved the mechanical properties of hydrogels [21][22][23]. Typically, natural wood can be used as support material after releasing the tight connections between cellulose fibers, generating tough wood structure hydrogels for enhanced mechanical strength, super-ion transport, or pressure sensors [10,24,25]. Natural wood is usually valued because of its highly anisotropic structure; however, the hard crystalline structure of cellulose makes it difficult to make the wood hydrogel flexible [26,27].…”

Current international research into cellulose as a functional nanomaterial for advanced applications

“…Rechargeable batteries and supercapacitors are the two most popular types of electrochemical energy storage devices, and they have attracted increasing attention and enjoyed great success both in academic research and commercialization over the past few decades [416,[435][436][437]. With a high aspect ratio, and abundant surface functional groups to interact with ions, nanocellulose is an ideal starting material for energy storage devices based on ion transport [438,439]. It has been widely investigated as various important functional components in batteries and supercapacitors, such as current collectors, binders, electrolytes/separators, and electrodes [439][440][441][442].…”

“…With a high aspect ratio, and abundant surface functional groups to interact with ions, nanocellulose is an ideal starting material for energy storage devices based on ion transport [438,439]. It has been widely investigated as various important functional components in batteries and supercapacitors, such as current collectors, binders, electrolytes/separators, and electrodes [439][440][441][442]. The diverse structural tunability of nanocellulose (e.g., pores, fibril orientation, fibril diameter/length, surface functional groups, surface charge, surface energy, and surface wettability, degree of crystallinity, crystal phase structure, etc.)…”

Facile fabrication of carbon microtube arrays from waste wood for use as self-supporting supercapacitor electrodes

“…13 The special structural advantages could solve the problem for the stable self-supporting structures of biomass carbon and avoid the need for further bonding of carbons from other sources with a conductive agent or a polymer. 14 It is difficult to directly tune the structure and pore size of wood-based carbon materials because of the decomposition of cellulose, hemicellulose, and lignin during the direct carbonization process. 15,16 In addition, it remains a challenge to obtain high-performance supercapacitors by effectively increasing the specific surface area while retaining the advantages of the natural structure of wood.…”