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Designing a multifunctional device that combines solar energy conversion and energy storage is an appealing and promising approach for the next generation of green power and sustainable society. In this work, we fabricated a single-piece device incorporating undoped WSe2, Re- or Nb-doped WSe2 photocathode, and zinc foil anode system enabling a light-assisted rechargeable aqueous zinc metal cell. Comparison of structural, optical, and photoelectric characteristics of undoped and doped WSe2 has further confirmed that ionic insertion of donor metal (rhenium and niobium) plays an important role in enhancing photoelectrochemical energy storage properties. The electrochemical energy storage cell consisting of Re-doped WSe2 (as the photoactive cathode and zinc metal as anode) showed the best photodriven enhancement in the specific capacitance of around 45% due to efficient harvesting of visible light irradiation. The assembled device exhibited a loss of 20% of its initial specific capacitance after 1500 galvanostatic charge–discharge cycles at 50 mA g–1. The cell also provided a specific energy density of 574.21 mWh kg1– and a power density of 5906 mW kg1– at 15 mA g–1. Under otherwise similar conditions, the pristine WSe2 and Nb-doped WSe2 showed photoenhanced induced capacitance of 43% and 27% at 15 mA g–1 and supplied an energy density of 436.4 mWh kg1– and 202 mWh kg1–, respectively. As a result, a reasonable capacitance improvement obtained by the Re-WSe2 photoenhanced zinc-ion capacitor could provide a facile and constructive way to achieve a highly efficient and low-cost solar-electrochemical capacitor system. [ABSTRACT FROM AUTHOR]

The main emphasis of the present Highlight paper is to summarise reported works aiming to understand the effect of sulfur and nitrogen doping on graphene nanoplatelets for high capacity electrodes in solid-state rechargeable energy storage devices. Lithium-ion batteries are considered to be one of the most promising energy storage devices which have the potential of integrating the high energy granted by lithium-ion batteries and long cycling life of supercapacitors in the same system. However, the present Li-ion batteries provide only high power density due to the low electrical conductivity of the anode materials. Moreover, there is a need to increase the capacity and kinetic imbalances between the anode and cathode by designing high-power and stable structures for the anode and cathode materials. Graphene nanoplatelets (GnPs) have been intensively explored as anode materials in lithium ion batteries due to their unique structure and outstanding electrochemical properties. The synthesis procedure, structure and electrochemical performance of such materials are discussed extensively in this manuscript. [ABSTRACT FROM AUTHOR]

Two‐dimensional nanomaterials, as one of the most widely used substrates for energy storage devices, have achieved great success in terms of the overall capacity. Despite the extensive research effort dedicated to this field, there are still major challenges concerning capacitance modulation and stability of the 2D materials that need to be overcome. Doping of the crystal structures, pillaring methods and 3D structuring of electrodes have been proposed to improve the material properties. However, these strategies are usually accompanied by a significant increase in the cost of the entire material preparation process and also a lack of the versatility for modification of the various types of the chemical structures. Hence in this work, versatile, cheap, and environmentally friendly method for the enhancement of the electrochemical parameter of various MXene‐based supercapacitors (Ti3C2, Nb2C, and V2C), coated with functional and charged organic molecules (zwitterions—ZW) is introduced. The MXene‐organic hybrid strategy significantly increases the ionic absorption (capacitance boost) and also forms a passivation layer on the oxidation‐prone surface of the MXene through the covalent bonds. Therefore, this work demonstrates a new, cost‐effective, and versatile approach (MXene‐organic hybrid strategy) for the design and fabrication of hybrid MXene‐base electrode materials for energy storage/conversion systems. [ABSTRACT FROM AUTHOR]

Owing to the surge of energy storage devices, lithium and beyond‐lithium metal ion batteries (MIBs) have gained considerable research attention. The large size and multivalent ions drastically deteriorate the performance of conventional battery electrode materials which demands unique types of structures in order to fulfill the electrode requirements of next‐generation MIBs. Developing atomically thin nanosheets confined in 2D heterostructures is a favorable choice to synergistically handle the deficiencies of individual 2D materials and achieve distinct physical and electrochemical properties, retaining their 2D features. This article sheds light on the significance and characteristics of graphene‐based and beyond‐graphene 2D heterostructures as electrode materials in lithium‐ion, sodium‐ion, potassium‐ion, magnesium‐ion, and aluminum‐ion batteries. In this regard, the pathways for the selection of 2D heterostructures electrode materials and their possible geometric configurations are first recognized. Second, the fundamental science, underlying charge storage mechanisms, and robust interfacial charge transfer processes in 2D heterostructures are discussed comprehensively in the context of recent computational studies. Third, the recent state‐of‐the‐art experimental approaches for the fabrication of novel 2D heterostructures and their performance as anode and cathode materials for MIBs are discussed systematically. Finally, the current challenges facing 2D heterostructures and potential future research directions in the context of advanced MIBs are highlighted. [ABSTRACT FROM AUTHOR]

The advents in flexible and smart technology like wearable electronics have accelerated the demand for high‐performance energy‐storage devices. These devices could significantly reduce the size of the next‐generation wearable smart electronics. A selection of suitable printing technology and its product typically offer a reasonable manufacturing pathway like high deposition rate, low materials waste, scalable fabrication, and high‐performance production. Therefore, the production of novel functional inks with desirable rheological properties that authorize high‐resolution printing, are some major challenges of this technology. This work has an emphasis on the recent advancements in supporting and utilizing liquid metals chemistry to synthesis high‐quality and scalable 2D nanomaterials by liquid‐phase free exfoliation and facile sonication‐assisted methods. These are novel concepts in synthesizing 2D nanomaterials particularly for those which either have not intrinsic layered crystal structures or those with strong interaction between their crystal layers which are difficult to synthesized using conventional approaches. It also provides some potentials to make sustainable ink formulation of such 2D nanostructures for the fabrication of high‐quality screen‐printed patterns for sustainable energy applications. Subsequently, it deals with the possibilities and challenges of printing such 2D nanomaterials (namely, 2D metal oxides) for micro‐supercapacitor and micro‐battery applications on an industrially viable scale. [ABSTRACT FROM AUTHOR]

The derived lysine from biomass fermentation is a naturally abundant renewable resource. However, the small molecular size of lysine limits its processing and application. On the other side, carbonization of polylysine into high‐valued carbon materials is one of convenient options to apply for energy storage devices. Herein, we prepare polylysine@silica hybrid nanostructure through thermal polymerization of lysine and biosilicification of tetraethoxysilane (TEOS). Subsequently, nitrogen‐containing porous carbon flakes (NPCF) are synthesized upon carbonization. Interestingly, the synthesized NPCF presents hierarchical porous framework structure with interconnected micro‐meso‐macro pores. Consequently, the NPCF delivers an excellent supercapacitor performance. For instance, our characterizations display specific capacitance up to 242 F/g at 1 mV/s and 186 F/g at 1 A/g, and could keep 96.3% initial capacity after 10,000 cycles at 10 A/g. These achievements are because of hierarchical porosity, proper nitrogen content, and accessible surface area of nanostructured NPCF. Therefore, our work creates a novel and sustainable route for fabricating NPCF with promising applications in the supercapacitors. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48214. [ABSTRACT FROM AUTHOR]

• Flexible, ultralight, current collector and binder-free energy storage device. • Cost-effective device fabrication method. • Excellent electrochemical performance and cycling stability. Development of flexible, ultralight, scalable and non-leaking energy storage devices such as electrochemical capacitors that are on par with commercial standards and offer compliances while retaining safety remain a significant challenge for the realization of wearable devices. Generally, the bottleneck to the improvement of such devices is the need to use ecofriendly electrode and electrolyte materials with desirable surface, electrochemical and mechanical properties. Thus, this study provides a new platform for development of flexible, ultralight, freestanding electrochemical capacitor using a composite of cellulose/SWCNTs (CL/CNTs) electrode films and a new cellulose/NaHSO 4 hydrogel electrolyte. Herein, we took advantage of the renewability and flexibility of cellulose in combination with the high conductivity and storage capacity of SWCNTs to create a high specific capacitance, energy and power density. Moreover, the new cellulose/NaHSO 4 hydrogel electrolyte provided stable cycling, leading to non-leakage device exhibiting ∼100% capacitance retention after 3000 cycles. Cellulosic composites are developed as sustainable free-standing electrode and electrolyte for high performance electrochemical charge storage. [Display omitted] [ABSTRACT FROM AUTHOR]