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Ion exchange is a promising synthetic method for alleviating severe cation mixing in traditional layered oxide materials for lithium-ion batteries, leading to enhanced structural stability. However, the underlying mechanisms of ion exchange are still not fully understood. Such a fundamental study of the ion-exchange mechanism is needed for achieving the controllable synthesis of layered oxides with a stable structure. Herein, we thoroughly unearth the underlying mechanism that triggers the ion exchange of Ni-rich materials in aqueous solutions by examining time-resolved structural evolution combined with theoretical calculations. Our results reveal that the reaction pathway of ion exchange can be divided into two steps: protonation and lithiation. The proton is the key to achieving charge balance in the ion exchange process, as revealed by X-ray adsorption spectroscopy and inductive coupled plasma analysis. In addition, the intermediate product shows high lattice distortion during ion exchange, but it ends up with a most stable product with high lattice energy. Such apparent discrepancies in lattice energy between materials before and after ion exchange emphasize the importance of synthetic design in structural stability. This work provides new insights into the ion-exchange synthesis of Ni-rich oxide materials, which advances the development of cathode materials for high-performance lithium-ion batteries.

Lithium (Li)-ion batteries have stimulated the societal transformation to clean energy systems. This carry-on electricity is revolutionizing how society communicates, functions, and evolves efficiently by enabling mobile electronics, zero-emission electric vehicles, and stationary energy storage. In preparation for the sustainable energy future, however, there are growing concerns about depleting critical elements used in the Li technology (e.g., lithium, cobalt, and nickel), especially for large-scale applications that will accelerate the rate of elemental consumption. Various non-Li-based rechargeable batteries composed of earth-abundant elements, such as sodium, potassium, magnesium, and calcium, have been proposed and explored as alternative systems to promote sustainable development of energy storage. In this perspective, we discuss challenges in Li-ion batteries in the sustainability aspect and provide our opinions on the potential applications of non-Li-based batteries. We also highlight the current status, important progress, and remaining challenges of the Li-alternative technologies.

Inkjet-printed quantum dot light-emitting diodes (QLEDs) are emerging as a promising technology for next-generation displays. However, the progress in fabricating QLEDs using inkjet printing technique has been slower compared to spin-coated devices, particularly in terms of efficiency and stability. The key to achieving high performance QLEDs lies in creating a highly ordered and uniform inkjet-printed quantum dot (QD) thin film. In this study, we present a highly effective strategy to significantly improve the quality of inkjet-printed CdZnSe/CdZnS/ZnS QD thin films through a pressure-assisted thermal annealing (PTA) approach. Benefiting from this PTA process, a high quality QD thin film with ordered packing, low surface roughness, high photoluminescence and excellent electrical property is obtained. The mechanism behind the PTA process and its profound impact on device performance have been thoroughly investigated and understood. Consequently, a record high external quantum efficiency (EQE) of 23.08% with an impressive operational lifetime (T₅₀) of up to 343,342 ​h@100 ​cd ​m⁻², and a record EQE of 22.43% with T₅₀ exceeding to 1,500,463 ​h@100 ​cd ​m⁻² are achieved in inkjet-printed red and green CdZnSe-based QLEDs, respectively. This work highlights the PTA process as an important approach to realize highly efficient and stable inkjet-printed QLEDs, thus advancing QLED technology to practical applications.

This study investigates the effect of defect engineering on the catalytic activity of a NiPS₃ monolayer catalyst for the hydrogen evolution reaction (HER). Three different types of vacancies on the basal plane of the monolayer are explored through a multi-step mechanism involving the dissociative adsorption of a water molecule and subsequent electrochemical adsorption of the dissociated proton. Co-formation of vacancies in both Ni and S sites is found to be the most effective in enhancing the catalytic performance of the monolayer. A key resource for the reaction thermodynamics is the S-substitution-like physisorption of a water molecule on a vacant S site, followed by the dissociative occupation of OH and H into vacant sites of S and Ni elements, boosted by the NiS di-vacancy configuration with low activation energy barriers. Investigation reveals the highest contribution of bonding orbitals to the monolayer-H bond makes it the most desirable defect engineering approach for transition metal phosphorus chalcogenides with high HER activities. Overall, this study highlights the significance of controlled defect engineering in augmenting the catalytic performance of NiPS₃ monolayer catalysts for HER.

Transparent conductive oxide (TCO) films, known for their role as carrier transport layers in solar cells, can be adversely affected by hydrolysis products from encapsulants. In this study, we explored the morphology, optical-electrical properties, and deterioration mechanisms of In₂O₃-based TCO films under acetic acid stress. A reduction in film thickness and carrier concentration due to acid-induced corrosion was observed. X-ray photoelectron spectroscopy and inductively coupled plasma emission spectrometry analyses revealed that TCOs doped with less-reactive metals exhibited enhanced corrosion resistance. The efficiency of silicon heterojunction (SHJ) solar cells with tin-doped indium oxide, titanium-doped indium oxide, and zinc-doped indium oxide films decreased by 10%, 26%, and 100%, respectively, after 200 ​h of corrosion. We also found that tungsten-doped indium oxide could effectively safeguard SHJ solar cells against acetic acid corrosion, which offers a potential option for achieving long-term stability and lower levelized cost of solar cell systems. This research provides essential insights into selecting TCO films for solar cells and highlights the implications of ethylene-vinyl acetate hydrolysis for photovoltaic modules.

Indium-based oxides are promising electrocatalysts for producing formate via CO₂ reduction reaction, in which ∗OCHO is considered the key intermediate. Here, we identified that the ∗COOH pathway could be preferential to produce formate on In₂O₃ of In/In₂O₃ heterojunction due to the synergistic effect of oxygen species and vacancy. Specifically, ∗CO₂ and ∗COOH were observed on In₂O₃ and related to formate production by in situ Raman spectroscopy. The theoretical calculations further demonstrated that the energy barrier of the ∗COOH formation on In₂O₃ was decreased in the presence of oxygen vacancy, similar to or lower than that of the ∗OCHO formation on the In surface. As a result, a formate selectivity of over 90% was obtained on prepared In/In₂O₃ heterojunction with 343 ​± ​7 ​mA ​cm⁻² partial current density. Furthermore, when using a Si-based photovoltaic as an energy supplier, 10.11% solar–to–fuel energy efficiency was achieved.

Binders play a crucial role in enhancing the cycling stability of silicon anodes in next-generation Li-ion batteries. However, traditional linear polymer binders have difficulty withstanding the volume expansion of silicon during cycling. Herein, inspired by the fact that animals’ claws can grasp objects firmly, a claw-like taurine-grafted-poly (acrylic acid) binder (Tau-g-PAA) is designed to improve the electrochemical performance of silicon anodes. The synergistic effects of different polar groups (sulfo and carboxyl) in Tau-g-PAA facilitate the formation of multidimensional interactions with silicon nanoparticles and the diffusion of Li ions, thereby greatly improving the stability and rate performance of silicon anodes, which aligns with results from density functional theory (DFT) simulations. As expected, a Tau-g-PAA/Si electrode exhibits excellent cycling performance with a high specific capacity of 1003 ​mA ​h ​g⁻¹ ​at 1 ​C (1 ​C ​= ​4200 ​mA ​h ​g⁻¹) after 300 cycles, and a high rate performance. The design strategy of using polar small molecule-grafted polymers to create claw-like structures could inspire the development of better binders for silicon-based anodes.

Sodium-ion batteries (SIBs) with low cost and high safety are considered as an electrochemical energy storage technology suitable for large-scale energy storage. Hard carbon, which is inexpensive and has both high capacity and low sodium storage potential, is regarded as the most promising anode for commercial SIBs. However, the commercialization of hard carbon still faces technical issues of low initial Coulombic efficiency, poor rate performance, and insufficient cycling stability, due to the intrinsically irregular microstructure of hard carbon. To address these challenges, the rational design of the hard carbon microstructure is crucial for achieving high-performance SIBs, via gaining an in-depth understanding of its structure–performance correlations. In this context, our review firstly describes the sodium storage mechanism from the perspective of the hard carbon microstructure's formation. We then summarize the state-of-art development of hard carbon, providing a critical overview of emergence of hard carbon in terms of precursor selection, microstructure design, and electrolyte regulation to optimize strategies for addressing practical problems. Finally, we highlight directions for the future development of hard carbon to achieve the commercialization of high-performance SIBs. We believe this review will serve as basic guidance for the rational design of hard carbon and stimulate more exciting research into other types of energy storage devices.

Lithium–sulfur batteries are considered potential high-energy-density candidates to replace current lithium-ion batteries. However, several problems remain to be solved, including low conductivity, huge volume change, and a severe shuttle effect on the cathode side, as well as inevitable lithium dendrites on the anode side. Rare earth compounds, which play vital roles in various industries, show latent capacity as cathode hosts or interlayers to tackle the inherent problems of lithium–sulfur batteries. However, the application of rare earth compounds in lithium–sulfur batteries has not been reviewed so far, despite they showing obvious advantages for tuning polysulfide retention and conversion. In this mini-review, we start by introducing the concept of lithium–sulfur batteries and providing background information on rare earth-based materials. In the main body, we explore rare earth compounds as cathode hosts or interlayers, then discuss various types of each. Finally, we offer an outlook on the existing challenges and possible opportunities for using rare earth compounds as cathode hosts or interlayers for lithium–sulfur batteries.

Powered by optical energy, photocatalytic reduction for fuel production promises to be an ideal long-term solution to a number of key energy challenges. Photocatalysts with enhanced light absorption, fast electron/hole separation rates, and exposed activity sites are essential to improve photocatalytic efficiency. Semiconductors are constrained by their own intrinsic properties and have limited performance in photocatalysis, but defect engineering provides an opportunity to modulate the physical and chemical properties of semiconductors. Defect engineering has been shown to be effective in regulating electron distribution and accelerating photocatalytic kinetics during photocatalysis. This review introduces the definition and categorization of defects, then explains the main effects of defect engineering on photoabsorption, carrier separation/migration, and surface reduction reactions. We then review the milestones in the design of defect-engineered photocatalysts for key chemical reactions, including hydrogen evolution, CO₂ reduction, and N₂ reduction, and tabulate their respective effects on catalytic performance. Finally, we provide insights and perspectives on the challenges and potential of defect engineering for photoreduction reactions.