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Abstract: This review provides an up‐to‐date review about the small molecule interlayers (SMIs) in organic solar cells (OSCs). Compared to polymer interlayers, SMIs exhibit intrinsic advantages such as easy synthesis and purification, monodispersity, well‐defined chemical structure, and high batch‐to‐batch reproducibility. Recently, various SMIs have been reported with landmark efficiencies of over 10% in both conventional and inverted OSCs, exhibiting promising potential in commercial application. In this review, the authors summarize the progress of SMIs from a device fabrication point of view, paying particular attention to the material categories, molecular design, preparation process, and applicable device structure. In addition, the working mechanisms of different SMIs are also discussed, including the structure–property relationships and the corresponding impact on device performance. Finally, a brief outlook is provided that includes opportunities and challenges in this emerging area. [ABSTRACT FROM AUTHOR]

Two alcohol‐soluble organic molecules are synthesized and introduced into inverted organic solar cells as the cathode interlayer. A power conversion efficiency as high as 9.22% is obtained by using the more hydrophobic molecule FTBTF‐N as the cathode interlayer. Morphological studies suggest that design of the backbone can help to enhance short‐circuit current density and fill factor. [ABSTRACT FROM AUTHOR]

Achieving reversible plating/stripping of zinc (Zn) anodes is crucial in aqueous Zn‐ion batteries (AZIBs). However, undesired dendrite growth and parasitic side reactions severely deteriorate battery lifespan. The construction of stable protective coating is an effective strategy to enhance anode stability. In this study, a multifunctional nanodiamond (ND) inorganic layer is designed and constructed on both Zn and Cu electrodes that can both effectively inhibit dendrite growth and suppress Zn anode corrosion. Experimental results and theoretical calculations demonstrate that this artificial protective layer, with ultra‐high surface energy, enables the controlled creation of abundant nucleation sites (in the order of 1012 cm−2) for the homogenization of ion flux and electric field on the anode. It is found that zinc ions preferentially adhere to the diamond surfaces with lower diffusion barriers, leading to uniform zinc deposition. A symmetric cell with the ND‐protected Zn (Zn‐ND) anode exhibits reversible plating/stripping behavior for an impressive duration of over 3600 h at 1 mA cm−2. Furthermore, the MnO2||Zn full battery retains 90% of its initial capacity after 3500 cycles at 2 A g−1, and assembled hybrid capacitor operates smoothly over 65 000 cycles at 10 A g−1. These results underscore the potential of this coating as a promising solution for achieving highly stable Zn anodes for aqueous batteries. [ABSTRACT FROM AUTHOR]

The engineering of anode‐electrolyte interphase for highly reversible and dendrite‐free Zn plating‐stripping continues to pose a significant challenge in the progression of aqueous Zn‐ion batteries (AZIBs). In this study, a novel approach is introduced that involves the design of a hierarchical carbon nanotube (CNT)‐based host through functionalization with cetyltrimethylammonium cations (CTA+). This hierarchical host enables dynamically switchable repulsive shielding to regulate Zn plating. The CNT scaffold, featured with high flexibility and conductivity, facilitates expandable accommodation of continuous Zn plating. Concurrently, the entangled CTA+ cations, acting as manipulators to form switchable repulsive shields, dynamically suppress the growth of Zn dendrites, and result in uniform Zn plating within cationic CNT (C‐CNT) hosts. The cationic shielding effect is further elucidated through density functional theory calculations. By incorporating the self‐adaptive C‐CNT host, Zn symmetric cells exhibit an impressively stable cycling lifespan exceeding 6500 h at 1 mA·cm−2 and achieve a cumulative capacity of 6000 mAh·cm−2 at 4 mA·cm−2. Full batteries, by coupling the C‐CNT@Zn anode and MnO2 cathode, demonstrate an 88% capacity retention after 2000 cycles at 2 A·g−1. The design of the self‐adaptive C‐CNT host offers a promising approach in electrode‐electrolyte interphase engineering toward the practical applications of Zn‐based energy storage systems. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have attracted much attention in the past decade and their power conversion efficiency has been rapidly increasing to 25.2%, which is comparable with commercialized solar cells. Currently, the long‐term stability of PSCs remains as a major bottleneck impeding their future commercial applications. Beyond strengthening the perovskite layer itself and developing robust external device encapsulation/packaging technology, integration of effective barriers into PSCs has been recognized to be of equal importance to improve the whole device's long‐term stability. These barriers can not only shield the critical perovskite layer and other functional layers from external detrimental factors such as heat, light, and H2O/O2, but also prevent the undesired ion/molecular diffusion/volatilization from perovskite. In addition, some delicate barrier designs can simultaneously improve the efficiency and stability. In this review article, the research progress on barrier designs in PSCs for improving their long‐term stability is reviewed in terms of the barrier functions, locations in PSCs, and material characteristics. Regarding specific barriers, their preparation methods, chemical/photoelectronic/mechanical properties, and their role in device stability, are further discussed. On the basis of these accumulative efforts, predictions for the further development of effective barriers in PSCs are provided at the end of this review. [ABSTRACT FROM AUTHOR]

As a promising candidate for next‐generation energy storage devices, Zn metal battery excels with their good safety, high specific capacity, and economic attractiveness. However, it still suffers from a narrow electrochemical window, notorious dendrite formation, and sluggish Zn ion transfer. Aqueous electrolyte engineering has been regarded as an effective way to improve these. It is shown that by adding sodium polystyrene sulfonate (PSS) polymers into a dilute 1 m Zn(OTf)2 aqueous electrolyte, compact water shells with stronger hydrogen bonding and more ordered structures are formed around the polymer chains. As a result, a fast transport channel to the zinc ions is provided. The PSS chains also protect the zinc electrode from directly contacting the water molecules and thus suppress water decomposition. With these merits, a Zn//Cu cell demonstrates a high coulombic efficiency of ≈99% after 1500 h cycling. Meanwhile, a record‐high cumulative Zn plating capacity of 10 000 mA h cm−2 is obtained using a Zn||Zn cell. In addition, the Zn//C@V2O5 full cell achieves almost 100% capacity retention after 1000 cycles. This work provides a new strategy for designing advanced electrolyte systems excelling in ion transport kinetics. [ABSTRACT FROM AUTHOR]

Lamellar transition-metal dichalcogenides (MX2) have promising applications in electrochemical energy storage and conversion devices due to their two-dimensional structure, ultrathin thickness, large interlayer distance, tunable bandgap, and transformable phase nature. Interlayer engineering of MX2 nanosheets with large specific surface area can modulate their electronic structures and interlayer distance as well as the intercalated foreign species, which is important for optimizing their performance in different devices. In this review, a summary on recent progress of MX2 nanosheets and the significance of their interlayer engineering is presented firstly. Synthesis of interlayer-expanded MX2 nanosheets with various strategies is then discussed in detail. Emphasis is focused on their applications in rechargeable batteries, pseudocapacitors, hydrogen evolution reaction (HER) catalysis and treatments of environmental contaminants, demonstrating the importance of interlayer engineering on controlling performance of MX2. The current challenges of the interlayer-expanded MX2 and outlooks for further advances are finally discussed. [ABSTRACT FROM AUTHOR]

In the pursuit of better electrode kinetics and mass transportation for electrochemical energy applications, 3D graphene-based electrodes have been receiving increasing research interest. Distinguished from other kinds of 3D graphene structures, the well-developed, vertically aligned graphene nanosheet arrays (VAGNAs) could be grown on a variety of substrates by plasma-enhanced chemical vapor deposition (PECVD), forming a 3D interconnected structure with intimate contact with substrates and largely exposed edges, and easily accessible open surfaces of the graphene nanosheets. Ascribing to the combined superior inherent properties of graphene and the special structure configuration, e.g., large surface area, excellent electron transfer capability, outstanding mechanical strength, great chemical and thermal stabilities, and enhanced electrochemical activity, VAGNAs have demonstrated promising applications in supercapacitors, batteries, and fuel cell catalysts. This progress report provides a brief review on the nucleation and growth of VAGNAs, their growth mechanism and properties, and highlights the recent important progress in their electrochemical energy conversion and storage applications, in the views of their pros and cons in comparison with other 3D graphene-based structures. Challenges and perspectives for future advance are discussed in the end. [ABSTRACT FROM AUTHOR]

Layered transition metal oxides are promising cathode materials for sodium‐ion batteries applicable for low‐cost energy storage systems. However, their cycle stability needs to be substantially improved to meet the requirements of practical applications. Specifically, the issues related to electrolyte stability and the formation of an unstable cathode–electrolyte interface (CEI) remain unsolved. Herein, it is shown that an electrolyte with high fluorine content may induce a robust fluorinated CEI on Na2/3Ni1/3Mn2/3O2 cathode, a representative transitional metal oxide, which can efficiently passivate its surface and suppress continuous electrolyte decomposition during cycling. As a result, the cells deliver a remarkably improved rate capability and cycle stability. Density functional simulations further validate the superior stability of fluorinated electrolyte on cathodes with low highest occupied molecule orbital energy and high dissociation energy barriers. This finding demonstrates the favorable role of fluorinated electrolytes for improving the long‐term cycle stability of Na2/3Ni1/3Mn2/3O2 cathode toward grid‐scale applications. [ABSTRACT FROM AUTHOR]

Supercapacitors supply high power densities but suffer from low energy densities and small specific capacitances. The design and implementation of unique capacitor electrodes are expected to overcome these challenges. Herein, flexible diamond fibers (a fibrous core/shell structure of diamond/carbon fibers) are produced through overgrowing conductive carbon fibers core with a thin boron‐doped diamond film as a shell using a chemical vapor deposition technique. The resultant fibers combine the properties of boron‐doped diamond with those of carbon fibers. This allows these binder‐free diamond fibers to be employed as the positive electrode in the fabrication of zinc‐ion supercapacitors. Together with a negative electrode fabricated from zinc nanosheet coated diamond fibers, this diamond supercapacitor delivers a high and stable specific capacitance. More importantly, it delivers high gravimetric and volumetric energy and power densities, even under severe bending states. The performance of this flexible supercapacitor is superior to previous diamond and carbon fiber‐based supercapacitors. Such flexible diamond supercapacitors are promising energy storage devices for various flexible electronics. [ABSTRACT FROM AUTHOR]

Fullerene derivatives, which possess extraordinary geometric shapes and high electron affinity, have attracted significant attention for thin film technologies. This study demonstrates an important photovoltaic application using carboxyl-functionalized carbon buckyballs, C60 pyrrolidine tris-acid (CPTA), to fabricate electron transport layers (ETLs) that replace traditional metal oxide-based ETLs in efficient and stable n-i-p-structured planar perovskite solar cells (PSCs). The uniform CPTA film is covalently anchored onto the surface of indium tin oxide (ITO), significantly suppressing hysteresis and enhancing the flexural strength in the CPTA-modified PSCs. Moreover, solution-processable CPTA-based ETLs also enable the fabrication of lightweight flexible PSCs. The maximum-performing device structures composed of ITO/CPTA/CH3NH3PbI3/2,2′,7,7′-tetrakis-( N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene (spiro-OMeTAD)/Au yield power conversion efficiencies of more than 18% on glass substrates and up to 17% on flexible substrates. These results indicate that the CPTA layers provide new opportunities for solution-processed organic ETLs by substantially simplifying the procedure for fabricating PSCs for portable applications. [ABSTRACT FROM AUTHOR]

Nanostructured V2O5 is emerging as a new cathode material for lithium ion batteries for its distinctly high theoretic capacity over the current commercial cathodes. The main challenges associated with nanostructured V2O5 cathodes are structural degradation, instability of the solid-electrolyte interface layer, and poor electron conductance, which lead to low capacity and rapid decay of cyclic stability. Here, a novel composite structure of V2O5 nanoparticles encapsulated in 3D networked porous carbon matrix coated on carbon fibers (V2O5/3DC-CFs) is reported that effectively addresses the mentioned problems. Remarkably, the V2O5/3DC-CF electrode exhibits excellent overall lithium-storage performance, including high Coulombic efficiency, excellent specific capacity, outstanding cycling stability and rate property. A reversible capacity of ≈183 mA h g−1 is obtained at a high current density of 10 C, and the battery retains 185 mA h g−1 after 5000 cycles, which shows the best cycling stability reported to date among all reported cathodes of lithium ion batteries as per the knowledge. The outstanding overall properties of the V2O5/3DC-CF composite make it a promising cathode material of lithium ion batteries for the power-intensive energy storage applications. [ABSTRACT FROM AUTHOR]

In article number 2002737 Denis Y. W. Yu, Yanwu Zhu, Wenjun Zhang and co‐workers discuss the continuous electrolyte decomposition of common carbonate‐based electrolytes, which accelerates the capacity decay of Na2/3Ni1/3Mn2/3O2. It is shown that a fluoroethylene carbonate electrolyte can suppress the successive electrolyte decomposition, thus enabling significantly improved cycle stability for Na2/3Ni1/3Mn2/3O2. Such work provides new solutions to develop low cost and durable sodium‐ion batteries for grid‐scale applications. [ABSTRACT FROM AUTHOR]

Keywords: cathode-electrolyte interfaces; density functional simulations; fluoroethylene carbonate; sodium-ion batteries; transitional metal oxides EN cathode-electrolyte interfaces density functional simulations fluoroethylene carbonate sodium-ion batteries transitional metal oxides 1 1 1 03/05/21 20210303 NES 210303 In article number 2002737 Denis Y. W. Yu, Yanwu Zhu, Wenjun Zhang and co-workers discuss the continuous electrolyte decomposition of common carbonate-based electrolytes, which accelerates the capacity decay of Na SB 2/3 sb Ni SB 1/3 sb Mn SB 2/3 sb O SB 2 sb . Cathode-electrolyte interfaces, density functional simulations, fluoroethylene carbonate, sodium-ion batteries, transitional metal oxides It is shown that a fluoroethylene carbonate electrolyte can suppress the successive electrolyte decomposition, thus enabling significantly improved cycle stability for Na SB 2/3 sb Ni SB 1/3 sb Mn SB 2/3 sb O SB 2 sb . [Extracted from the article]

Zinc-Ion Supercapacitors: Flexible Diamond Fibers for High-Energy-Density Zinc-Ion Supercapacitors (Adv. These diamond zinc-ion supercapacitors have promise as energy suppliers for flexible and wearable electronics. Boron-doped diamonds, energy densities, flexible electronics, flexible supercapacitors, zinc-ion supercapacitors. [Extracted from the article]

Keywords: AIMD simulations; Na metal-Te cell; redox reaction kinetics; sodium dendrites; Te/carbon nanorods cathode The assembled Na metal-Te full batteries show a highly reversible three-step redox kinetics process, suppressed polytellurides shuttling and stable sodium plating/stripping. AIMD simulations, Na metal-Te cell, redox reaction kinetics, sodium dendrites, Te/carbon nanorods cathode. [Extracted from the article]

Electrochemical metal cells utilizing tellurium and sodium chemistry are being extensively explored for developing advanced high‐performance batteries. The daunting challenges, however, still remain with low rate capability/volumetric capacity, unclear redox reaction processes, and the notorious sodium dendrites. Here, a cell design that features a novel Te/carbon nanorods cathode and a tailored ether‐based electrolyte is reported. It is the first report of Na metal‐Te full batteries with performance comparable to those of reported Na‐S and Na‐Se batteries at low ratings. By using the semimetal Te instead of the insulating S or Se, the Na‐Te batteries actually outperform reported Na‐S and Na‐Se batteries at high ratings. Ab initio molecular dynamics simulations, UV–vis spectrum, ex situ X‐ray photoelectron spectroscopy, and scanning electron microscopy results clearly reveal a three‐step redox process and stability of the Na metal‐Te cells. These comprehensive results demonstrate the feasibility of practical Na metal‐Te batteries with high volumetric energy density and a viable cell fabrication cost. [ABSTRACT FROM AUTHOR]

It is demonstrated that dendrite growth and byproduct formation can be suppressed during Zn plating, and the competitive hydrogen evolution reaction is restrained by using a 3 m Zn(CF SB 3 sb SO SB 3 sb ) SB 2 sb electrolyte. Furthermore, based on this electrolyte, a novel hybrid supercapacitor comprising Zn foil and porous carbon derived from chemically activated graphene is developed which delivers high energy density and an ultra-long lifespan. Aqueous electrolytes, energy storage, graphene, hybrid supercapacitors, Zn metal anodes. [Extracted from the article]

Integrating a battery‐type electrode to build a hybrid supercapacitor is a promising approach to improve the overall energy density of a supercapacitor‐type energy storage device without sacrificing its power output. However, this strategy is usually achieved at the expense of cycling lifespan. In this work, a hybrid supercapacitor comprising Zn foil and porous carbon derived from chemical activated graphene (aMEGO) is developed, and the trade‐off between energy density and cycling life is well‐balanced by the utilization of 3 m Zn(CF3SO3)2 electrolyte with high Zn stripping/plating efficiency. Such a hybrid supercapacitor demonstrates an energy density of 106.3 Wh kg−1 and a power density of 31.4 kW kg−1, and significantly a wide operation voltage of 1.9 V is achieved in aqueous electrolyte. Benefitting from the high Zn stripping/plating efficiency, the Zn‐aMEGO hybrid‐supercapacitor also exhibits an ultralong cycling life up to 80 000 cycles with capacity retention of 93%, which is comparable to that of conventional electrochemical double‐layer capacitors. [ABSTRACT FROM AUTHOR]