Recent Strategies in Preparation of Cellulose Nanocrystals and Cellulose Nanofibrils Derived from Raw Cellulose Materials

The recent strategies in preparation of cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) were described. CNCs and CNFs are two types of nanocelluloses (NCs), and they possess various superior properties, such as large specific surface area, high tensile strength and stiffness, low density, and low thermal expansion coefficient. Due to various applications in biomedical engineering, food, sensor, packaging, and so on, there are many studies conducted on CNCs and CNFs. In this review, various methods of preparation of CNCs and CNFs are summarized, including mechanical, chemical, and biological methods. The methods of pretreatment of cellulose are described in view of the benefits to fibrillation

Advanced Nanocellulose‐Based Composites for Flexible Functional Energy Storage Devices

Abstract With the increasing demand for wearable electronics (such as smartwatch equipment, wearable health monitoring systems, and human–robot interface units), flexible energy storage systems with eco‐friendly, low‐cost, multifunctional characteristics, and high electrochemical performances are imperative to be constructed. Nanocellulose with sustainable natural abundance, superb properties, and unique structures has emerged as a promising nanomaterial, which shows significant potential for fabricating functional energy storage systems. This review is intended to provide novel perspectives on the combination of nanocellulose with other electrochemical materials to design and fabricate nanocellulose‐based flexible composites for advanced energy storage devices. First, the unique structural characteristics and properties of nanocellulose are briefly introduced. Second, the structure–property–application relationships of these composites are addressed to optimize their performances from the perspective of processing technologies and micro/nano‐interface structure. Next, the recent specific applications of nanocellulose‐based composites, ranging from flexible lithium‐ion batteries and electrochemical supercapacitors to emerging electrochemical energy storage devices, such as lithium‐sulfur batteries, sodium‐ion batteries, and zinc‐ion batteries, are comprehensively discussed. Finally, the current challenges and future developments in nanocellulose‐based composites for the next generation of flexible energy storage systems are proposed.Recent advances on nanocellulose‐based composites consisting of nanocellulose and other electrochemical materials for emerging flexible energy‐storage devices are comprehensively discussed, with a focus on structure–property–application relationships to optimize their performance. The current challenges and future developments regarding design and fabrication of nanocellulose‐based composites for the next generation of energy‐storage systems are discussed and proposed. imageNational Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809Key Technology Research and Development Program of TianjinFederal Ministry for Economic Affairs and Energy http://dx.doi.org/10.13039/501100006360Ministry for Science and Culture of Lower Saxony http://dx.doi.org/10.13039/501100010570WIPANOChina Scholarship Council http://dx.doi.org/10.13039/501100004543Niedersächsisches Ministerium für Wissenschaft und Kultur http://dx.doi.org/10.13039/501100010570Bundesministerium für Wirtschaft und Energie http://dx.doi.org/10.13039/501100006360Innovation Project of Excellent Doctoral Dissertation of Tianjin University of Science and TechnologyTianjin Research Innovation Project for Postgraduate Students http://dx.doi.org/10.13039/50110001906

Nanocellulose-Assisted Construction of Multifunctional MXene-Based Aerogels with Engineering Biomimetic Texture for Pressure Sensor and Compressible Electrode

Highlights Hyperelastic and superlight multifunctional MXene/nanocellulose composite aerogels with high conductivity are designed by constructing biomimetic texture. The MXene/nanocellulose aerogels as flexible pressure sensors exhibit appealing linear sensitivity performance (817.3 kPa−1). The as-prepared compressible supercapacitor with MXene/nanocellulose electrodes reveals superior electrochemical performance (849.2 mF cm−2 at 0.8 mA cm−2).Abstract Multifunctional architecture with intriguing structural design is highly desired for realizing the promising performances in wearable sensors and flexible energy storage devices. Cellulose nanofiber (CNF) is employed for assisting in building conductive, hyperelastic, and ultralight Ti3C2Tx MXene hybrid aerogels with oriented tracheid-like texture. The biomimetic hybrid aerogels are constructed by a facile bidirectional freezing strategy with CNF, carbon nanotube (CNT), and MXene based on synergistic electrostatic interaction and hydrogen bonding. Entangled CNF and CNT “mortars” bonded with MXene “bricks” of the tracheid structure produce good interfacial binding, and superior mechanical strength (up to 80% compressibility and extraordinary fatigue resistance of 1000 cycles at 50% strain). Benefiting from the biomimetic texture, CNF/CNT/MXene aerogel shows ultralow density of 7.48 mg cm−3 and excellent electrical conductivity (~ 2400 S m−1). Used as pressure sensors, such aerogels exhibit appealing sensitivity performance with the linear sensitivity up to 817.3 kPa−1, which affords their application in monitoring body surface information and detecting human motion. Furthermore, the aerogels can also act as electrode materials of compressive solid-state supercapacitors that reveal satisfactory electrochemical performance (849.2 mF cm−2 at 0.8 mA cm−2) and superior long cycle compression performance (88% after 10,000 cycles at a compressive strain of 30%)

Properties of Nanocelluloses and Their Application as Rheology Modifier in Paper Coating

In this study, different nanocellulose (NC) products were manufactured from corncob residue (CCR) through sulfuric acid hydrolysis, formic acid hydrolysis, and TEMPO-mediated oxidation methods (the products were referred as SCN, FCN, and TCN, respectively). The properties of NC products and their impact on rheological behavior of paper coatings were comparatively studied. Results showed that compared to SCN and TCN, FCN exhibited large dimensions, limited negative surface charge, and poor stability in their aqueous suspensions, while the FCN aqueous suspension displayed the highest viscoelastic modulus due to the formation of highly entangled network. In paper coatings, SCN exhibited superior thickening and promoted rheological function due to their highly charged surface and strong interactions with pigments and immobilized water molecules, in comparison with other NC products. This study verified that the NC derived from CCR could be utilized as green and renewable additives to improve rheological properties for paper coatings