Nitroxide radicals have fast and reversible redox reactions and high electron transfer rates, while the instability in electrolytes and low conductivity restrict their applications on electrodes. Here, we employ two-dimensional MXene Ti 3 C 2 T x as a conductive film-forming agent for 4-amino-TEMPO (TEMPO = 2,2,6,6-tetramethylpiperidine-1-oxyl) to prepare a freestanding and flexible electrode. Pendant nitroxide radicals experience two-electron storage through reversible redox reactions and realize synergistically boosted charge storage with redox-active Ti 3 C 2 T x nanosheets. A systematic electrochemical investigation demonstrates that nitroxide radicals greatly contribute to the surface capacitance of the hybrid electrode, which significantly improves its diffusion-capacitive dualmodel energy storage and cycling stability. Further, the assembled symmetric supercapacitor achieves a high energy density of 60.3 Wh kg −1 and the all-in-one asymmetric supercapacitor shows a wide potential window of 1.8 V, demonstrating great promise in energy storage devices.

Nature builds numerous structurally complex composites with fascinating mechanical robustness and functionalities by harnessing biopolymers and amorphous calcium carbonate (ACC).The key to successfully mimicking these natural designs is efficiently stabilizing ACC, but developing highly efficient, biodegradable, biocompatible, and sustainable stabilizing agents remains a grand challenge since anhydrous ACC is inherently unstable toward crystallization in the wet state. Inspired by the stabilized ACC in crustacean cuticles, we report the efficient stabilization ability of the most abundant biopolymer−cellulose nanofibrils (CNFs) for ACC. Through the cooperative stabilizing effect of surface carboxyl groups and a rigid segregated network, the CNFs exhibit long-term stability (more than one month) and achieved a stabilization efficiency of 3.6 and 4.4 times that of carboxymethyl cellulose (CMC) and alginate, respectively, even higher than poly(acrylic acid). The resulting CNF/ACC dispersions can be constructed into transparent composite films with the high strength of 286 MPa and toughness up to 28.5 MJ/m 3 , which surpass those of the so far reported synthetic biopolymer-calcium carbonate/phosphate composites. The dynamic interfacial interaction between nanocomponents also provides the composite films with good selfhealing properties. Owing to their good wet stability, the composite films present high humidity sensitivity for monitoring respiration and finger contact.

Advanced multiplexing optical labels with multiple information channels provide a powerful strategy for large‐capacity and high‐security information encryption. However, current optical labels face challenges of difficulty to realize independent multi‐channel encryption, cumbersome design, and environmental pollution. Herein, multiplexing chiroptical bio‐labels integrating with multiple optical elements, including structural color, photoluminescence (PL), circular polarized light activity, humidity‐responsible color, and micro/nano physical patterns, are constructed in complex design based on host‐guest self‐assembly of cellulose nanocrystals and bio‐gold nanoclusters. The thin nanocellulose labels exhibit tunable circular polarized structural color crossover the entire visible wavelength and circularly polarized PL with the highest‐recorded dissymmetry factor up to 1.05 due to the well‐ordered chiral organization of templated gold nanoclusters. Most importantly, these elements can independently encode customized anti‐counterfeiting information to achieve five independent channels of high‐level anti‐counterfeiting, which are rarely achieved in traditional materials and design counterparts. Considering the exceptional seamless integration of five independent encryption channels and the recyclable features of labels, the bio‐labels have great potential for the next generation anti‐counterfeiting materials technology.

Fiber-shaped supercapacitors (FSSCs) with high rate-capability, light-weight, and knittability are promising members of future flexible energy storage clubs. However, limited by the trade-off between capacity density and transport kinetics of...