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.

Bacterial cellulose (BC), with non-toxicity, high purity, and biocompatibility, has been considered as a versatile candidate for various biomedical applications. Recently, the fabrication of BC-based composite scaffolds compounded with other ingredients such as nanoparticles and polymers has received extensive investigation, which enabled the development of numerous promising biomedical products. Additionally, BC-derived nanocrystals (BCNCs) and nanofibrils (BCNFs) have proven to be promising reinforcing agents in a variety of polymeric scaffolds for biomedical applications. In this review, we summarize recent preparation strategies for BC-based and BCNCs- and BCNFs-containing composite scaffolds and their advances in biomedical applications, including wound healing, tissue engineering, and drug delivery, as well as tumor cell culture and cancer treatment. Finally, we present challenges and future perspectives for BC-based composite scaffolds for biomedical applications.

Developing superelastic and superhydrophilic carbon aerogels with intriguing mechanical properties is urgently desired for achieving promising performances in highly compressive supercapacitors and strain sensors. Herein, based on synergistic hydrogen bonding, electrostatic interaction, and π-π interaction within regularly arranged layered porous structures, conductive carbon aerogels with cellulose nanofibrils (CNF), carbon nanotubes (CNT) and reduced graphene oxide (RGO) are developed via bidirectional freezing and subsequent annealing. Benefiting from the porous architecture and high surface roughness, CNF/CNT/RGO carbon aerogels exhibit ultralow density (2.64 mg cm -3 ) and superhydrophilicity (water contact angle ≈0° at 106 ms). The honeycomb-like ordered porous structure can efficiently transfer stress in the entire microstructure, thereby endowing carbon aerogels with high compressibility and extraordinary fatigue resistance (10,000 cycles at 50% strain). These aerogels can be assembled into compressive solidstate symmetric supercapacitors showing excellent area capacitance (109.4 mF cm -2 at 0.4 mA cm -2 ) and superior long cycle compression performance (88% after 5000 cycles at compressive strain of 50%). Furthermore, the aerogels reveal good linear sensitivity (S = 5.61 kPa -1 ) and accurately capture human bio-signals as strain sensors. It is expected that such CNF/CNT/RGO carbon aerogels will provide a novel multifunctional platform for wearable electronics, electronic skin, and human motion monitoring.

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