The working principle of the triboelectric nanogenerator (TENG), contact electrification and electrostatic induction, has been used to harvest raindrop energy in recent years. However, the existing ...research is mainly concentrated on solid–liquid electrification, and adopts traditional electrostatic induction (TEI) for output. As a result, the efficiency of droplet electricity generators (DEGs) is severely constrained. Therefore, previous studies deem that the DEG output is limited by interfacial effects. This study reveals that this view is inappropriate and, in reality, the output strategy is the key bottleneck restricting the DEG performance. Here, a switch effect based on an electric‐double‐layer capacitor (EDLC) is introduced, and an equivalent circuit model is established to understand its working mechanism. Without pre‐charging, a single droplet can generate high voltage over 100 V and the output is directly improved by two‐orders of magnitude compared with TEI, which is precisely utilizing the interfacial effect. This work provides insightful perspective and lays solid foundation for DEG applications in large scale.
A droplet electricity generator (DEG) combining interfacial effect and switch effect is proposed to achieve an ultrahigh output without pre‐charging, and the working mechanism is explained based on an equivalent circuit model. Compared with traditional electrostatic induction (TEI) electricity generation, the output is directly improved by two orders of magnitude, which provides insightful perspective and lays a solid foundation for large‐scale DEG applications.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Asymmetric supercapacitors (ASCs) have attracted significant attentions worldwide owing to their wider voltage window compared with symmetric supercapacitors (SCs). Through combinations of two ...electrodes with different charge storage mechanisms or different redox reactions, extended operating voltage window can be realized for ASCs. In this article, first the ASCs are classified into two types based on different charge storage mechanisms: electric double‐layer capacitive (EDLC)//pseudocapacitive‐type ASCs and EDLC//battery‐type hybrid SCs. For the EDLC/pseudocapacitive‐type ASC, carbon materials are adopted as anode and transition metal oxides including MnO2, RuO2, etc., are utilized as cathodes. For EDLC//battery‐type hybrid SCs, carbon materials as anode are combined with metal oxide/hydroxide such as NiO, and Ni(OH)2, etc., as cathode. Recently, Li‐ion‐based ASCs composed of carbon materials and Li‐ion battery‐type electrode materials with a Li‐containing organic electrolyte show great potentials to be promising alternatives. Some metal oxides/nitrides including InO2, Bi2O3, Fe3O4, Fe2O3, and VN can work in a negative potential range. By coupling another battery/pseudocapacitive electrode, all redox‐type ASCs are assembled and their electrochemical performances are widely studied. Then, based on the above categories recent advances of ASCs are summarized. Finally, the challenges and prospects for the development of ASCs are pointed out from perspectives of this study.
The asymmetric supercapacitors (ASCs) composed of electric double layered capacitance electrode material and pseudocapacitive/battery‐type material or two redox‐type materials offer the prospect of widening working potential windows, resulting in significantly increased energy density. This review focuses on the different types of ASCs, providing a summary for the development, prospects, and challenges of ASCs.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Electric double layers (EDLs) formed in electrolyte‐gated field‐effect transistors (FETs) induce an extremely large local electric field that gives a highly efficient charge carrier control in the ...semiconductor channel. To achieve highly efficient triboelectric potential gating on the FET and explore diversified applications of electric double layer FETs (EDL‐FETs), a triboiontronic transistor is proposed to bridge triboelectric potential modulation and ion‐controlled semiconductor devices. Utilizing the triboelectric potential instead of applying an external gate voltage, the triboiontronic MoS2 transistor is efficiently operated owing to the formation of EDLs in the ion‐gel dielectric layer. The operation mechanism of the triboiontronic transistor is proposed, and high current on/off ratio over 107, low threshold value (75 μm), and steep switching properties (20 µm dec−1) are achieved. A triboiontronic logic inverter with desirable gain (8.3 V mm−1), low power consumption, and high stability is also demonstrated. This work presents a low‐power‐consuming, active, and a general approach to efficiently modulate semiconductor devices through mechanical instructions, which has great potential in human–machine interaction, electronic skin, and intelligent wearable devices. The proposed triboiontronics utilize ion migration and arrangement triggered by mechanical stimuli to control electronic properties, which are ready to deliver new interdisciplinary research directions.
A triboiontronic field‐effect transistor of molybdenum disulfide is proposed to bridge triboelectric potential modulation and ion‐controlled semiconductor devices. The operation mechanism of the triboiontronic transistor is investigated and high current on/off ratio (>107), low threshold value (75 µm), and steep switching properties (20 µm dec−1) are achieved.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•Shengli lignite via hydrothermal carbonization pre-treatment to prepared PCs.•The SSA of PCs is higher than the AC directly derived from lignite.•The PCs electrode exhibits high specific capacitance ...of 295Fg−1.•The PCs electrode shows excellent rate performance and superior cycling stability.
A series of porous carbons (PCs) were obtained from Shengli lignite (SL) via hydrothermal carbonization (HTC) pre-treatment and followed by chemical activation with KOH. The effects of preparation parameters including HTC temperature, KOH-hydrochar ratio and activation temperature on pore structure and the electrochemical performances of PCs were investigated in details. The PCs are mainly micropores structure according to the N2 adsorption-desorption isotherms test and the highest specific surface area (SSA) is up to 3162m2g−1. The SSA and total pore volume of PCs with HTC pre-treatment are larger than that without HTC treatment. The electrochemical performances of the symmetric electric double layer capacitor (EDLC) fabricated from these PC electrodes were tested by galvanostatic charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy. All the PCs as electrode for EDLC exhibit ideal capacitive behaviors in 6M KOH electrolyte. The specific capacitance of 200-HTC-800-3 can reach as high as 295Fg−1 at the current density of 40mAg−1 and still retained 210Fg−1 at the current density of 10Ag−1. It also shows excellent electrochemical cycle performance that after 15000 cycles the specific capacitance value almost not decay. The processes used to produce the PCs can reduce the energy consumption compared to the traditional carbonization-activation method.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Hybrid supercapacitors with their improved performance in energy density without altering their power density have been in trend since recent years. The hybrid supercapacitor delivers higher specific ...capacitance in comparison to the existing electric double layer capacitor (EDLC) and pseudocapacitors. Generally, the asymmetric behavior of hybrid supercapacitors which is the combination of EDLC and pseudocapacitor acts as an enhancer in its respective capacitance values. This asymmetric approach marks a new beginning towards the much-needed pollution free, long lasting and proficient energy-storing performance. Corresponding to their utilization in hybrid electric vehicles and similar sort of power necessity based devices; the research in developing new advanced storage devices finds an enormous and vast future ahead. The most significant factor for the energy efficient applications demands a considerably higher ratio of surface to the volume by incorporation of new materials. This review article gives an overview of recent advances in the development of hybrid supercapacitors, storage mechanism, criteria of formation, components, different electrode and electrolyte materials, electrochemical profile assessment, design fabrication and their applications.
•The current status and the advancement of supercapacitors are discussed in this review.•The principles, classification and the mechanism of energy storage are discussed.•Finally, various applications of supercapacitors have been discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Aqueous rechargeable Zn metal batteries (AZMBs) have attracted widespread attention due to their intrinsic high volumetric capacity and low cost. However, the unstable Zn/electrolyte interface causes ...Zn dendrite growth and side reactions, resulting in poor Coulombic efficiency and unsatisfactory lifespan. Herein, a SiO2 reinforced‐sodium alginate (SA) hybrid film is designed to regulate solid–liquid interaction energy and spatial distribution of all species in the electric double layer (EDL) near the Zn electrode. The unique interfacial layer gives rise to a uniform distribution of Zn2+ in the Helmholtz layer through solvation sheath modulation. Moreover, theoretical calculations show that the SO42− anions and free‐water are substantially reduced in the Helmholtz layer, effectively suppressing hydrogen evolution reaction and formation of by‐products through strong charge repulsion and hydrogen bond fixing of free‐water. The reconfigured EDL not only ensures homogenous and fast Zn2+ transport kinetics for dendrite‐free Zn deposition, but also eliminates interface parasitic side reactions. The Zn@SiO2‐SA electrode enables excellent cycling stability of symmetrical cells and high‐loading full AZMBs with a lifespan over 3000 h and an areal capacity of 2.05 mAh cm−2, thus laying a solid basis for realizing practical AZMBs.
An electric double‐layer reconstruction strategy is proposed to regulate solid–liquid interaction energy and spatial distribution of all species at the Zn interface. The reconfigured electric double layer not only ensures homogenous and fast Zn2+ transport kinetics for dendrite‐free Zn deposition, but also eliminates interface parasitic side reactions. Consequently, the Zn@SiO2‐sodium alginate electrode enables excellent cycling stability of symmetrical cells and high‐loading full aqueous rechargeable Zn metal batteries with a lifespan over 3000 h and an areal capacity of 2.05 mAh cm−2.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Interfaces between a liquid and a solid (L-S) are the most important surface science in chemistry, catalysis, energy, and even biology. Formation of an electric double layer (EDL) at the L-S ...interface has been attributed due to the adsorption of a layer of ions at the solid surface, which causes the ions in the liquid to redistribute. Although the existence of a layer of charges on a solid surface is always assumed, the origin of the charges is not extensively explored. Recent studies of contact electrification (CE) between a liquid and a solid suggest that electron transfer plays a dominant role at the initial stage for forming the charge layer at the L-S interface. Here, we review the recent works about electron transfer in liquid-solid CE, including scenerios such as liquid-insulator, liquid-semiconductor, and liquid-metal. Formation of the EDL is revisited considering the existence of electron transfer at the L-S interface. Furthermore, the triboelectric nanogenerator (TENG) technique based on the liquid-solid CE is introduced, which can be used not only for harvesting mechanical energy from a liquid but also as a probe for probing the charge transfer at liquid-solid interfaces.
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IJS, KILJ, NUK, PNG, UL, UM
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