Due to spontaneous organization of cellulose nanocrystals (CNCs) into the chiral nematic structure that can selectively reflect circularly polarized light within a visible-light region, fabricating stretching deformation-responsive CNC materials is of great interest but is still a big challenge, despite such a function widely observed from existing creatures, like a chameleon, because of the inherent brittleness. Here, a flexible network structure is introduced in CNCs, exerting a bridge effect for the rigid nanomaterials. The as-prepared films display high flexibility with a fracture strain of up to 39%. Notably, stretching-induced structural color changes visible to the naked eye are realized, for the first time, for CNC materials. In addition, the soft materials show humidity-and compressionresponsive properties in terms of changing apparent structural colors. Colored marks left by ink-free writing can be shown or hidden by controlling the environmental humidities. This biobased photonic film, acting as a new "smart skin", is potentially used with multifunctions of chromogenic sensing, encryption, and anti-counterfeit.

Li-S battery technology, with high theoretical capacity and energy density, has drawn much attention in recent years as a possible replacement for current Li-ion battery technologies. A major drawback of Li-S batteries is a severe capacity fading effect which, to a large extent, stems from the dissolution and diffusion of lithium polysulfides (LiPS) that are formed during both charge and discharge cycles. The self-discharge caused by the LiPS migration during the charge process (the so-called "shuttle effect") often leads to the capacity decay of Li-S batteries. Herein, hollow structured metal oxide (CoO, MnO, and NiO) submicro-spheres are prepared by a novel method and employed as efficient LiPS immobilizers. These Li-S batteries, based on the developed metal oxide spheres, possess outstanding rate capability and cycling stability. The best performing S/C/CoO electrode delivers excellent cycling stability with only a 0.066% capacity decay per cycle during 550 cycles. Moreover, its discharge capacity is as high as 428 mA h g at a 3C rate which is far superior to that of bare S/C (115 mA h g) at 3C. The fast kinetics of the electrocatalytic conversion of LiPS on the developed CoO electrode and its unique hollow structure are the key factors that lead to its outstanding performance as a Li-S battery cathode material.

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Hierarchical porous V–N–C with V–Nx sites demonstrates enhanced catalytic activity for polysulfide conversion, and thus shows excellent performance in Li–S batteries.

A magnetically separable nanocatalyst consisting of 2−5-nm Pt particles dispersed on carbon-encapsulated nickel nanoparticles has been artificially constructed. The magnetically separable function of the nanocatalyst is well demonstrated by recycled hydrogenation of nitrobenzene to aniline. The construction process has been clearly illuminated, which is composed of the nondestructive functionalization of magnetic Ni(C) nanocapsules with carboxylic acid end groups and then the immobilization of Pt nanoparticles. This strategy should be applicable to the construction of some other magnetically separable nanocatalysts.