Radioluminescent materials (scintillators) are widely applied in medical imaging, nondestructive testing, security inspection, nuclear and radiation industries, and scientific research. Recently, all‐inorganic lead halide perovskite nanocrystal (NC) scintillators have attracted great attention due to their facile solution processability and ultrasensitive X‐ray detection, which allows for large area and flexible X‐ray imaging. However, the light yield of these perovskite NCs is relatively low because of the strong self‐absorption that reduces the light out‐coupling efficiency. Here, NCs with self‐trapped excitons emission are demonstrated to be sensitive, reabsorption‐free scintillators. Highly luminescent and stable Cs3Cu2I5 NCs with a photoluminescence quantum yields of 73.7%, which is a new record for blue emission lead‐free perovskite or perovskite‐like NCs, is produced with the assistance of InI3. The PL peak of the Cs3Cu2I5 NCs locates at 445 nm that matches with the response peak of a silicon photomultiplier. Thus, Cs3Cu2I5 NCs are demonstrated as efficient scintillators with zero self‐absorption and extremely high light yield (≈79 279 photons per MeV). Both Cs3Cu2I5 NC colloidal solution and film exhibit strong radioluminescence under X‐ray irradiation. The potential application of Cs3Cu2I5 NCs as reabsorption‐free, low cost, large area, and flexible scintillators is demonstrated by a prototype X‐ray imaging with a high spatial resolution.

Metal halide perovskites have aroused tremendous interest in the past several years for their promising applications in display and lighting. However, the development of blue perovskite light‐emitting diodes (PeLEDs) still lags far behind that of their green and red cousins due to the difficulty in obtaining high‐quality blue perovskite emissive layers. In this study, a simple approach is conceived to improve the emission and electrical properties of blue perovskites. By introducing an alkali metal ion to occupy some sites of peripheral suspended organic ligands, the nonradiative recombination is suppressed, and, consequently, blue CsPb(Br/Cl)3 nanocrystals with a high photoluminescence quantum efficiency of 38.4% are obtained. The introduced K+ acts as a new type of metal ligand, which not only suppresses nonradiative pathways but also improves the charge carrier transport of the perovskite nanocrystals. With further engineering of the device structure to balance the charge injection rate, a spectrally stable and efficient blue PeLED with a maximum external quantum efficiency of 1.96% at the emission peak of 477 nm is fabricated.

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In this review, we evaluate and summarize the application of expanded graphite-based materials in rechargeable batteries, including alkaline ions (such as Na+, K+) storage and multivalent ion (such as Mg2+, Zn2+, Ca2+ and Al3+) storage batteries.

Supercapacitors have gained e wide attention because of high power density, fast charging and discharging, as well as good cycle performance. Recently, expanded graphite (EG) has been widely investigated as an effective electrode material for supercapacitors owing to its excellent physical, chemical, electrical, and mechanical properties. Based on charge storage mechanism, supercapacitors have been divided into symmetric, asymmetric, and hybrid supercapacitors. Here, we review the study progress of EG-based materials to be electrode materials. Furthermore, we discuss the application prospects and challenges of EG-based materials in supercapacitors.

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To inhibit the shuttle effect and promote the electrochemical performance of the Li/SeS 2 batteries, the threedimensional (3D) conductive composite of freestanding Fe 0.4 Co 8.6 S 8 nanotube/nanosheet arrays on carbon cloth (CC@ Fe 0.4 Co 8.6 S 8 ) is designed and synthesized to host SeS 2 . The integrated host appears in the form of the Fe 0.4 Co 8.6 S 8 nanosheets growing on the surface of nanotubes supported by carbon cloth, which provides a great surface area and offers secondary protection from nanosheets against shuttle of polyselenides/sulfides on the basis of nanotubes. Such enhanced physical confinement, along with chemical immobilization of the polar Fe 0.4 Co 8.6 S 8 , ensures high capability to adsorb polyselenides/sulfides. The wellconstructed conductive network facilitates the fast redox reaction to lessen the dissolution and diffusion of polyselenides/sulfides. It was demonstrated by the adsorption test and explained by the systematic self-discharge experiments. As a result, upon the elevated current density and/or SeS 2 loading, the deliberately designed architecture of CC@Fe 0.4 Co 8.6 S 8 can exhibit large reversible capacity as well as great energy density. Specifically, with the areal loading of 2 mg cm −2 , the CC@Fe 0.4 Co 8.6 S 8 /SeS 2 electrode delivers high discharge capacity of 888 mAh g −1 at 1.0 A g −1 and excellent rate capability (585 mAh g −1 at 4.0 A g −1 ). In addition, with the areal loading increasing to 3.6 mg cm 2 , the cathode still reaches an ultrahigh capacity of 703 mAh g −1 at 1.0 A g −1 . Upon further increasing SeS 2 loading to 4.8 mg cm 2 , the corresponding areal energy density reaches 8.05 mWh cm −2 at 0.2 A g −1 . This contribution adopts a less complex structure to address the issues in Li/SeS 2 batteries. The effectiveness of shuttle inhibition is explained quantitatively through a systematic study on self-discharge phenomena, besides the electrochemical performance.