The development of energy storage devices that can endure large and complex deformations is central to emerging wearable electronics. Hydrogels made from conducting polymers give rise to a promising ...integration of high conductivity and versatility in processing. However, the emergence of conducting polymer hydrogels with a desirable network structure cannot be readily achieved using conventional polymerization methods. Here we present a cryopolymerization strategy for preparing an intrinsically stretchable, compressible and bendable anisotropic polyvinyl alcohol/polyaniline hydrogel with a complete recovery of 100% stretching strain, 50% compressing strain and fully bending. Due to its high mechanical strength, superelastic properties and bi-continuous phase structure, the as-obtained anisotropic polyvinyl alcohol/polyaniline hydrogel can work as a stretching/compressing/bending electrode, maintaining its stable output under complex deformations for an all-solid-state supercapacitor. In particular, it achieves an extremely high energy density of 27.5 W h kg
, which is among that of state-of-the-art stretchable supercapacitors.
With the increased demand in energy resources, great efforts have been devoted to developing advanced energy storage and conversion systems. Graphene and graphene‐based materials have attracted great ...attention owing to their unique properties of high mechanical flexibility, large surface area, chemical stability, superior electric and thermal conductivities that render them great choices as alternative electrode materials for electrochemical energy storage systems. This Review summarizes the recent progress in graphene and graphene‐based materials for four energy storage systems, i.e., lithium‐ion batteries, supercapacitors, lithium‐sulfur batteries and lithium‐air batteries.
With the increased demand in energy resources, great efforts have been devoted to developing advanced energy storage and conversion systems. Graphene and graphene‐based materials have attracted great attention owing to their unique properties of high mechanical flexibility, large surface area, chemical stability, superior electric and thermal conductivities that render them great choices as alternative electrode materials for electrochemical energy storage systems. This Review summarizes the recent progress in graphene and graphene‐based materials for four energy storage systems, i.e., lithium‐ion batteries, supercapacitors, lithium‐sulfur batteries, and lithium‐air batteries.
Developing clean and sustainable energies as alternatives to fossil fuels is in strong demand within modern society. The oxygen evolution reaction (OER) is the efficiency‐limiting process in plenty ...of key renewable energy systems, such as electrochemical water splitting and rechargeable metal–air batteries. In this regard, ongoing efforts have been devoted to seeking high‐performance electrocatalysts for enhanced energy conversion efficiency. Apart from traditional precious‐metal‐based catalysts, nickel‐based compounds are the most promising earth‐abundant OER catalysts, attracting ever‐increasing interest due to high activity and stability. In this review, the recent progress on nickel‐based oxide and (oxy)hydroxide composites for water oxidation catalysis in terms of materials design/synthesis and electrochemical performance is summarized. Some underlying mechanisms to profoundly understand the catalytic active sites are also highlighted. In addition, the future research trends and perspectives on the development of Ni‐based OER electrocatalysts are discussed.
No precious metals allowed: Developing highly active and precious‐metal‐free catalysts for the oxygen evolution reaction (OER) is of great significance to the development of electrochemical water splitting and metal–air batteries. This minireview summarizes recent progress on the synthesis, catalytic performance, and underlying mechanisms of Ni‐based oxide/(oxy)hydroxide electrocatalysts for alkaline OER.
Considerable attention has been paid to the utilization of CO2, an abundant carbon source in nature. In this regard, porous catalysts have been eagerly explored with excellent performance for ...photo‐/electrocatalytic reduction of CO2 to high valued products. Metal–organic frameworks (MOFs), featuring large surface area, high porosity, tunable composition and unique structural characteristics, have been widely exploited in catalytic CO2 reduction. This Minireview first reports the current progress of MOFs in CO2 reduction. Then, a specific interest is focused on MOFs in photo‐/electrocatalytic reduction of CO2 by modifying their metal centers, organic linkers, and pores. Finally, the future directions of study are also highlighted to satisfy the requirement of practical applications.
Go photo! Benefitting from the adjustable pores, tunable composites and unique structure, MOFs have been extensively applied in photo‐/electrocatalytic reduction of CO2 with outstanding performances.
Energy storage and conversion technologies are vital to the efficient utilization of sustainable renewable energy sources. Rechargeable lithium‐ion batteries (LIBs) and the emerging sodium‐ion ...batteries (SIBs) are considered as two of the most promising energy storage devices, and electrocatalysis processes play critical roles in energy conversion techniques that achieve mutual transformation between renewable electricity and chemical energies. It has been demonstrated that nanostructured metal chalcogenides including metal sulfides and metal selenides show great potential for efficient energy storage and conversion due to their unique physicochemical properties. In this feature article, the recent research progress on nanostructured metal sulfides and metal selenides for application in SIBs/LIBs and hydrogen/oxygen electrocatalysis (hydrogen evolution reaction, oxygen evolution reaction, and oxygen reduction reaction) is summarized and discussed. The corresponding electrochemical mechanisms, critical issues, and effective strategies towards performance improvement are presented. Finally, the remaining challenges and perspectives for the future development of metal chalcogenides in the energy research field are proposed.
Metal chalcogenides including metal sulfides and selenides are intensively studied in the energy field due to their unique physicochemical properties. In this review, specific attention is given to the state‐of‐the‐art research progress in sodium‐ion batteries, lithium‐ion batteries, and electrocatalysis hydrogen evolution reaction, oxygen evolution reaction, and oxygen reduction reaction.
Semiconductor heterostructures of two-dimensional (2D) transition metal disulfide (TMD) have opened up approaches toward the integration of each function and implementations in novel energy and ...electronic devices. However, engineering TMD-based homostructures with tailored properties is still challenging. Herein, we demonstrate a solution-processed growth of vertically aligned 1T-MoS2 using liquid-phase exfoliated 2H-MoS2 as self-templates. The unique MoS2-based homostructures not only provide more exposed active sites in the edge and basal plane for the electrocatalytic hydrogen evolution reaction (HER) but also improve the mass transfer due to the introduction of high packing porosity. The resultant all-MoS2 electrocatalysts with an integration of polymorphous MoS2 nanostructures exhibit a superior HER activity with a low potential of 203 mV at 10 mA cm–2, a small Tafel slope of 60 mV dec–1, and a remarkable cyclic stability. This work thus provides a simple and efficient route for the creation of unprecedented MoS2-based homostructured materials with exciting properties, especially as an inexpensive alternative to platinum catalysts in electrochemical hydrogen evolution production.
Metal–organic frameworks (MOFs) and MOF‐derived nanostructures are recently emerging as promising catalysts for electrocatalysis applications. Herein, 2D MOFs nanosheets decorated with Fe‐MOF ...nanoparticles are synthesized and evaluated as the catalysts for water oxidation catalysis in alkaline medium. A dramatic enhancement of the catalytic activity is demonstrated by introduction of electrochemically inert Fe‐MOF nanoparticles onto active 2D MOFs nanosheets. In the case of active Ni‐MOF nanosheets (Ni‐MOF@Fe‐MOF), the overpotential is 265 mV to reach a current density of 10 mA cm−2 in 1 m KOH, which is lowered by ≈100 mV after hybridization due to the 2D nanosheet morphology and the synergistic effect between Ni active centers and Fe species. Similar performance improvement is also successfully demonstrated in the active NiCo‐MOF nanosheets. More importantly, the real catalytic active species in the hybrid Ni‐MOF@Fe‐MOF catalyst are unraveled. It is found that, NiO nanograins (≈5 nm) are formed in situ during oxygen evolution reaction (OER) process and act as OER active centers as well as building blocks of the porous nanosheet catalysts. These findings provide new insights into understanding MOF‐based catalysts for water oxidation catalysis, and also shed light on designing highly efficient MOF‐derived nanostructures for electrocatalysis.
A highly efficient 2D metal–organic frameworks (MOF)‐based hybrid electrocatalyst for the oxygen evolution reaction (OER) is demonstrated by in situ deposition of electrochemically inert Fe‐MOF nanoparticles onto the active Ni‐MOF nanosheets. This work provides new insights into understanding MOF‐based catalysts for water oxidation catalysis, and sheds light on developing MOF‐derived nanostructures for electrocatalysis.
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•Photo-electrochemical (PEC) devices based on perovskite solar cells are reviewed.•The electrode materials and performance evaluations of the devices are summarized.•The configuration ...design and integration strategy of the devices are discussed.
Photo-electrochemical (PEC) devices based on perovskite photovoltaics that convert abundant solar energy directly into stored electric energy or value-added chemicals (e.g., hydrogen, carbon products) have great potential to eliminate the intermittency issue of the solar energy supply. Currently, tremendous efforts have been made to achieve boosted overall conversion efficiency of PEC devices. In this review, we highlight the state-of-the-art representative configurations of the emerging perovskite solar cells-based PEC devices including self-charging power packs and unassisted solar water splitting/CO2 reduction based on the emerging perovskite solar cells. We also present a summary of recent progress in this field including the configuration design, integration strategies, electrode materials and their performance evaluations. Finally, the existing challenges and future perspectives are provided for the on-going research in this field.
Hydrogels are investigated broadly in flexible sensors which have been applied into wearable electronics. However, further application of hydrogels is restricted by the ambiguity of the sensing ...mechanisms, and the multi-functionalization of flexible sensing systems based on hydrogels in terms of cost, difficulty in integration, and device fabrication remains a challenge, obstructing the specific application scenarios. Herein, cost-effective, structure-specialized and scenario-applicable 3D printing of direct ink writing (DIW) technology fabricated two-dimensional (2D) transition metal carbides (MXenes) bonded hydrogel sensor with excellent strain and temperature sensing performance is developed. Gauge factor (GF) of 5.7 (0 - 191% strain) and high temperature sensitivity (-5.27% °C
) within wide working range (0 - 80 °C) can be achieved. In particular, the corresponding mechanisms are clarified based on finite element analysis and the first use of in situ temperature-dependent Raman technology for hydrogels, and the printed sensor can realize precise temperature indication of shape memory solar array hinge.
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