In this study, redox-active polyvinyl alcohol (PVA)-KOH-urea-LiClO4 alkaline gel electrolyte was prepared and used to assemble a Co oxide//Mn oxide wearable asymmetric supercapacitor (WASC). This ...experiment was achieved by choosing a deep eutectic solvent, urea-LiClO4, as the redox additive and aid a broad operating voltage, alongside an alkaline KOH-PVA gel to enhance redox performance and as plasticizer. The nanoporous Co oxide and Mn oxide electrodes were prepared using electroplating. The Co oxide//Mn oxide WASC with a PVA-KOH-urea-LiClO4 gel electrolyte can operate with an output voltage of 2.2 V and produce a high energy density of 125 Wh/kg at 2200 W/kg. The WASC showed good performance (186 F/g at 2 A/g) and 89.5% capacitance retention after 6000 charging/discharging cycles. Additionally, the WASC can maintain its electrochemical performance at various bending angles. Studied as the WASC electrode, in-situ/operando X-ray absorption near-edge spectroscopy revealed that the Co oxide suffers a reversible oxidation state-alteration reaction related to the redox pseudocapacitance reaction in PVA-KOH-urea-LiClO4. To show real life application, the WASCs were successfully applied to power a light-emitting diode and a digital watch.
•Nanoporous Co oxide and Mn oxide electrodes were prepared.•A redox-active PVA-KOH-urea-LiClO4 alkaline gel electrolyte was designed to improve operating voltage and pseudocapacitance.•Co-NCC//Mn-NCC WASCs exhibit high energy density of 125 Wh/kg at 2200 W/kg.•In-situ/operando XANES was used to identify the chemical state shift during charge-discharge cycling.
In this work, we successfully fabricated 3D network vanadium oxide (VOx) and manganese oxide (MnOx) nanofibers on conductive paper (PVA–acetamide–LiClO4-graphite/paper, PGP) as electrodes linked with ...an eco-friendly PVA–acetamide–LiClO4 (PAL) deep eutectic solvent-based gel electrolyte for high-voltage wearable asymmetric supercapacitors (HVWASCs). An ecologically compatible deep eutectic solvent-based electrolyte with self-supporting electroactive species has been generally accepted as a unique type of cost-effective and green electrolyte that possibly involves a bulk concentration of the electroactive species and a large working potential window, thereby achieving a high performance. The HVWASCs are able to work with a large operating voltage of 4.2 V, and supply outstanding energy and power densities (245 W hkg−1 at 0.18 W kg−1 and 95.3 kW kg−1 at 98 W h kg−1). The HVWASCs demonstrate remarkable cycling stability and durability after 6000 cycles, including bending and twisting (capacitance retention of 91.5%). The HVWASCs are a superior prospective candidate for wearable/flexible electronic devices and Internet of Things (IoT) applications.
With a simple electrochemical process, we prepared nano-architectured CuO electrodes with a 3D hierarchically porous structure and an excellent supercapacitive performance. These nano-architectured ...CuO electrodes were processed through co-deposition of a Ni–Cu layer on Ni foam, selective etching of Cu from the Ni–Cu film (leaving tentacle-like nanoporous Ni), and anodic deposition of CuO nanoribbons (NRs) on the tentacle-like nanoporous Ni/Ni foam substrate. Because of its unique nano-architecture, the prepared CuO nanoribbon-on-Ni-nanoporous/Ni foam (CNRNP) electrode shows exceptional performance of energy storage relative to a conventional version of the electrode. The CNRNP electrode has also a superior kinetic performance relative to CuO nanoflake-on-Ni foam (CNFNF) and flake-like CuO (FLC) electrodes. Besides its excellent cyclic stability, an exceptionally large specific capacitance of 880 and 800 F g −1 (deducting the substrate capacitance from the total) for the CNRNP electrode is obtained at scan rates of 10 and 200 mV s −1 , respectively. The excellent pseudocapacitive characteristics of CNRNP electrodes associated with the variation of the Cu oxidation state during charge and discharge cycles were elucidated with in situ X-ray absorption near-edge structure (XANES) spectra.
•Building envelope and air conditioning energy performance mode is developed.•Multiobjective algorithm optimizes the envelope and air conditioning configuration.•Tradeoff configurations for two ...conflict objectives are obtained.•Optimized configuration reduced the construction cost and CO2 emission.
Configurations of the building envelope and the air conditioning system have a considerable effect on annual building energy efficiency. Taiwan government proposed two green building indices, namely the Envelope Energy Load (ENVLOAD) and the Performance of Air Conditioning System (PACS), as energy performance models of building envelopes and air conditioning systems. Relatively few studies, however, have been mainly conducted, using multiobjective optimization design for building envelope and air condition systems, with a goal to treat both the building energy systems and the envelope. Consequently, this study is to make contribution to this related filed by proposing a multi-objective optimal building envelope and air conditioning system energy performance decision model (MOBELM).
This model was used to design the optimal configurations of building envelopes and air conditioning systems based on the ENVLOAD and PACS constrictions and the two conflicting objectives. The first refers to the minimal construction cost when the building envelope and air condition system are built. The second is concerned with the minimal CO2 emission when the envelope materials are manufactured and used to form the building envelope. In the case study, the optimized configurations that dominated the original unoptimized design could validate the MOBELM.
Electrodeposition of Al, Mn, Ni, Zn, Sn, and Cu are successfully demonstrnated in the ionic liquids (ILs) composed of 1-methyl-3-alkylimidazolium or
N-methyl-
N-alkylpyrrolidinium cations with ...dicyanamide (DCA) anions. The DCA-based room-temperature ILs exhibit lower viscosities than those ILs based on
BF
4
-
,
PF
6
-
, and bis(trifluoromethylsulfonyl)imide (TFSI) anions. While most of the metal chlorides are insoluble in the
BF
4
-
,
PF
6
-
, and TFSI-based ILs, they exhibit good solubility in DCA-based ILs due to the strong complexing ability of DCA toward the transition metal ions. It is possible to alter the regular reduction sequence for particular metal ions in the DCA-based ILs.
Polymer gel electrolytes have shown potential for enhancing operation stability and cycle longevity in energy storage devices; however, their use in osmotic power conversion remains unexplored, ...because one would expect reduced ionic conductance at the nanoscale, which in turn can impact their performance output. Here we report the first polymer gel electrolyte-based osmotic power generator by introducing polyvinyl alcohol (PVA) as a solid matrix. We present the experimental evidence showing that with the PVA gel electrolyte, the ion transport and osmotic power can be enhanced under conditions in which the electric double layer overlap effect in nanochannels is significant; thus, a substantial increase of the power output as high as nearly two times can be achieved as compared to the corresponding aqueous electrolytes. The observations are explained by the adsorption of excess counterions onto PVA confined at the nanoscale, supported by our modeling performed using the modified Poisson and Nernst-Planck equations by considering a charged PVA layer in a nanochannel. The system presented offers a new avenue toward the exploitation of high-performance and safe osmotic power generators.
A polymer gel electrolyte-based nanofluidic osmotic power generator with substantially enhanced power performance is demonstrated.
A 3D network composed of V2O5 nanofibers was manufactured on a novel conductive printing paper urea–LiClO4–PVA (ULP) deep eutectic solvent gel-doped graphite/printing paper, U-paper for use as ...electrodes linked with a ULP neutral gel electrolyte for 3D network V2O5 wearable symmetric pseudocapacitors (WSSCs). The function of the ULP gel is not only that it can be doped into the conductive ink to decrease the resistance of the conductive printing paper but also that it increases the stability of V2O5-based electrodes. Moreover, 3D network V2O5 WSSCs containing the ULP gel can support high operating voltages of 4.0 V with great specific capacitance (160 F/g) and offer a high energy density (355 W h/kg at 0.2 kW/kg). The 3D network V2O5 WSSCs exhibit a superior cycling stability/durability after 5000 cycles (capacitance retention of ∼91%). Operando X-ray absorption spectroscopy experiments show the reversibility and pseudocapacitive properties of V2O5 from the ULP gel and offer the information of the oxidation states of vanadium during charge–discharge cycles. The 3D network V2O5 WSSCs with the ULP gel electrolyte show great potential prospective candidates for smarter 3D wearable energy-storage devices and Internet-of-Things applications.
Apigenin (Apig) is used as a model drug due to its many beneficial bio-activities and therapeutic potentials. Nevertheless, its poor water solubility and low storage stability have limited its ...application feasibility on the pharmaceutical field. To address this issue, this study developed nanoemulsions (NEs) using an anti-oxidative polymeric amphiphile, d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS), hydrogenated soy lecithin (HL), black soldier fly larvae (BSFL) oil, and avocado (AV) oil through pre-homogenization and ultrasonication method. Addition of TPGS (weight ratios 100 and 50% as compared to HL) into NEs effectively reduced particle size and phase transition region area of NEs with pure HL. Incorporation of Apig into NEs made particle size increase and provided a disorder effect on intraparticle molecular packing. Nevertheless, the encapsulation efficiency of NEs for Apig approached to about 99%. The chemical stability of Apig was significantly improved and its antioxidant ability was elevated by incorporation with BSFL oil and AV oil NEs, especially for NEs with single TPGS. NEs with single TPGS also exhibited the best Apig skin deposition. For future application of topical Apig delivery, NEs-gel was formed by the addition of hyaluronic acid (HA) into NEs. Their rheological characteristics were dominated by the surfactant ratios of HL to TPGS.
Flexible electrochemical supercapacitors (FESCs) are emerging as innovative energy storage systems, characterized by their stable performance, long cycle life, and portability/foldability. Crucial ...components of FESCs, such as electrodes and efficient electrolytes, have become the focus of extensive research. Herein, we examine deep eutectic solvent (DES)–based polymer gel systems for their cost-effective accessibility, simple synthesis, excellent biocompatibility, and exceptional thermal and electrochemical stability. We used a mixture a DES, LiClO4–2-Oxazolidinone as the electroactive species, and a polymer, either polyvinyl alcohol (PVA) or polyacrylamide (PAAM) as a redox additive/plasticizer. This combination facilitates a unique ion-transport process, enhancing the overall electrochemical performance of the polymer gel electrolyte. We manufactured and used LiClO4–2-Oxazolidinone (LO), polyvinyl alcohol–LiClO4–2-Oxazolidinone (PVA–LO), and polyacrylamide–LiClO4–2-Oxazolidinone (PAAM–LO) electrolytes to synthesize an MnO2 symmetric FESC. To evaluate their performance, we analyzed the MnO2 symmetric FESC using various electrolytes with cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). The FESC featuring the PVA–LO electrolyte demonstrated superior electrochemical and mechanical performances. This solid-state MnO2 symmetric FESC exhibited a specific capacitance of 121.6 F/g within a potential window of 2.4 V. Due to the excellent ionic conductivity and the wide electrochemical operating voltage range of the PVA–LO electrolyte, a high energy density of 97.3 Wh/kg at 1200 W/kg, and a long-lasting energy storage system (89.7% capacitance retention after 5000 cycles of GCD at 2 A/g) are feasibly achieved. For practical applications, we employed the MnO2 symmetric FESCs with the PVA–LO electrolyte to power a digital watch and a light-emitting diode, further demonstrating their real-world utility.
► Electrodeposition of Zn was successfully demonstrnated in the water- and air-stable BMP-DCA ionic liquid. While ZnCl
2 is insoluble in the BMP-TFSI ionic liquid, it dissolves easily in the BMP-DCA. ...► Amperometric titration experiments indicated that Zn(II) probably complexed as Zn(DCA)
3- with DCA- anion. ► Chronoamperometric experiments showed that the electrodeposition of Zn on GC and Mg alloy substrates involved 3D-instantaneous nucleation/growth process. ► A lower deposition rate would bring out a more uniform and compact Zn coating layer (which is also thicker) and, consequently, this coating revealed a protection capability for the Mg substrate against corrosion.
Electrochemical reaction of Zn(II)/Zn on glassy carbon electrode(GC) and Mg alloy substrates was investigated in the room-temperature ionic liquid,
N-butyl-
N-methyl-pyrrolidinium dicyanamide (BMP-DCA) containing ZnCl
2 at 323
K. Amperometric titration experiments suggest that Zn(II) reacted with DCA anions forming Zn(DCA)
3
− complex anion, which also could be reduced to Zn metal via a single-step electron transfer process. By chronoamperometric measurements, the electrodeposition of Zn on GC and Mg alloy substrates involved three-dimensional instantaneous nucleation under diffusion control at 323
K. The Zn deposits are also systematically characterized by the techniques of powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Zn layer deposited at a lower current density on Mg alloy substrates was more compact and uniform when compared to that deposited at a higher current density; consequently, this coating revealed a protection capability for the Mg substrate against corrosion.
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