High Open-circuit Voltage Research Articles

Synergistic passivation and energy level alignment by graphene quantum dots for high performance inverted CsPbI3 perovskite solar cells

Inorganic CsPbI3 perovskite solar cells (PSCs) have garnered considerable attention due to their high thermal stability and promising application in tandem devices. However, further advancement of the performance of CsPbI3 PSCs is restricted by severe nonradiative recombination, which is related to substantial defects and mismatched energy levels. Herein, the versatile graphene quantum dots (GQDs) are introduced to modify the CsPbI3 surface to improve interface contact and mitigate energy loss. GQD modification can not only effectively passivate surface defects via coordinating with the undercoordinated Pb2+ but also improve energy level alignment, contributing to efficient charge extraction and suppression of nonradiative recombination. Consequently, GQDs-based inverted CsPbI3 devices deliver a champion power conversion efficiency (PCE) of 18.98% with a high open-circuit voltage (VOC) of 1.141 V and are greatly superior to the control device obtaining a poor PCE of 13.29% with a VOC of 0.986 V. Moreover, GQDs can form a protective layer at the perovskite interface to resist external invasion, significantly boosting the device stability. Our findings establish the promising application of GQD modification as a compelling strategy for achieving high performance inorganic photovoltaic devices.

Electronic and optical properties of CsSnI3/MoS2 heterostructure as ultrabroadband photoelectric device

Infrared photoelectric detection and imaging technology has a wide range of applications in satellite remote sensing, safety monitoring, biomimetic vision, autonomous driving and other fields. Due to CsSnI3 having a lower bandgap, it has great application potential in the field of infrared and near-infrared photoelectric detection. The CsSnI3/MoS2 heterostructure is first designed to achieve absorption from mid infrared to ultraviolet. In this study, we systematically investigated the structural, electrical, and optical properties of CsSnI3/MoS2 heterostructure using Density Functional Theory (DFT). All of these heterostructures exhibit type-II band alignment. γ-CsSnI3/MoS2 shows more efficient charge transfers than α-CsSnI3/MoS2 and the γ-(110)-CsI/MoS2 heterostructures transfer the most electrons and have the biggest band offset, indicating a higher open circuit voltage and lower dark current. The γ-(110)-CsI/MoS2 heterostructures is stable and have the best enhancement effect compared to other heterostructures and enhances the absorption of the latter in ultraviolet to mid-infrared regions. This demonstrates that heterostructures composed of the specified termination surface and the two-dimensional material may achieve different functions, providing a guideline for experimentation to produce high-performance optoelectronic devices.

A General Strategy Based on Hetero‐Charge Coupling Effect for Constructing Single‐Atom Sites

AbstractSingle‐atom catalysts have emerged as cutting‐edge hotspots in the field of material science owing to their excellent catalytic performance brought about by well‐defined metal single‐atom sites (M SASs). However, huge challenges still lie in achieving the rational design and precise synthesis of M SASs. Herein, we report a novel synthesis strategy based on the hetero‐charge coupling effect (HCCE) to prepare M SASs loaded on N and S co‐doped porous carbon (M1/NSC). The proposed strategy was widely applied to prepare 17 types of M1/NSC composed of single or multi‐metal with the integrated regulation of the coordination environment and electronic structure, exhibiting good universality and flexible adjustability. Furthermore, this strategy provided a low‐cost method of efficiently synthesizing M1/NSC with high yields, that can produce more than 50 g catalyst at one time, which is key to large‐scale production. Among various as‐prepared unary M1/NSC (M can be Fe, Co, Ni, V, Cr, Mn, Mo, Pd, W, Re, Ir, Pt, or Bi) catalysts, Fe1/NSC delivered excellent performance for electrocatalytic nitrate reduction to NH3 with high NH3 Faradaic efficiency of 86.6 % and high NH3 yield rate of 1.50 mg h−1 mgcat.−1 at −0.6 V vs. RHE. Even using Fe1/NSC as a cathode in a Zn‐nitrate battery, it exhibited a high open circuit voltage of 1.756 V and high energy density of 4.42 mW cm−2 with good cycling stability.

A General Strategy Based on Hetero-Charge Coupling Effect for Constructing Single-Atom Sites.

Single-atom catalysts have emerged as cutting-edge hotspots in the field of material science owing to their excellent catalytic performance brought about by well-defined metal single-atom sites (M SASs). However, huge challenges still lie in achieving the rational design and precise synthesis of M SASs. Herein, we report a novel synthesis strategy based on the hetero-charge coupling effect (HCCE) to prepare M SASs loaded on N and S co-doped porous carbon (M1/NSC). The proposed strategy was widely applied to prepare 17 types of M1/NSC composed of single or multi-metal with the integrated regulation of the coordination environment and electronic structure, exhibiting good universality and flexible adjustability. Furthermore, this strategy provided a low-cost method of efficiently synthesizing M1/NSC with high yields, that can produce more than 50 g catalyst at one time, which is key to large-scale production. Among various as-prepared unary M1/NSC (M can be Fe, Co, Ni, V, Cr, Mn, Mo, Pd, W, Re, Ir, Pt, or Bi) catalysts, Fe1/NSC delivered excellent performance for electrocatalytic nitrate reduction to NH3 with high NH3 Faradaic efficiency of 86.6 % and high NH3 yield rate of 1.50 mg h-1 mgcat. -1 at -0.6 V vs. RHE. Even using Fe1/NSC as a cathode in a Zn-nitrate battery, it exhibited a high open circuit voltage of 1.756 V and high energy density of 4.42 mW cm-2 with good cycling stability.

Design and study of novel benzodithiazole-based hole transport materials for improved performance of perovskite solar cells: A DFT approach

The present research used end-capped molecular engineering to fabricate novel hole transport materials based on the benzodithiazole (BBT) core, designated as BBT-M1 to BBT-M5 HTMs. The computational techniques such as DFT and TD-DFT were employed to characterize the effect of terminal acceptors in designed molecules. Their results were compared with parent (BBT-R) and Spiro (MeOTAD) HTMs. Under TD-DFT investigation, absorption peaks of designed molecules were identified within the range of 380–559 nm, indicating their operation near UV and near/mid visible region. It was observed that designed materials have more compatible and deeper HOMO levels ranging from −5.242 to −5.161 eV, which leads to high open circuit voltage. They also exhibit better planarity, increased solubility and reactivity, moderate stability, and a narrow band gap ranging from 1.93 to 2.36 eV. Furthermore, the reorganization energy of holes (0.145–0.205 eV) is significantly lower than that of electrons (0.221–0.376 eV), indicating an overall tendency towards hole transport material. In BBT-M1 to BBT-M5 HTMs, the charge transfer integral of hole (0.229–0.353 eV), hole hopping rate (5.218×1014–6.969×1014 s–1), open circuit voltage (1.311–1.392 V) and fill factor (90.50–90.93 %) are remarkably better than BBT-R and Spiro (MeOTAD). Based on these outstanding attributes, it is proposed that BBT-M1 to BBT-M5 molecules are potential HTM candidates to replace conventional HTMs such as spiro (MeOTAD).

FeNi-LDH COATED WITH ORANGE-PEEL CARBON AEROGEL FOR OXYGEN EVOLUTION REACTION.

In this work, the waste orange-peel was used as carbon source, and the orange-peel derived carbon material can be obtained through simple pyrolysis. Then, we designed the structure of orange-peel carbon aerogel grown on iron-nickel layered double hydroxides in situ to achieve the effect of carbon coating (FeNi-LDH/CA). The oxygen evolution reaction catalytic performance of FeNi-LDH/CA is excellent, far exceeding that of commercial RuO2. In 1 M KOH, the overpotential of FeNi-LDH/CA is only 250 mV (10 mA cm-2), obviously better than that of commercial RuO2 (295 mV). FeNi-LDH/CA shows good cycling stability, and after long-term i-t testing, the performance only decays by 3% after running at 100 mA cm-2 for 100 h. When used as an anode, the voltage of water-splitting is only 1.48 V at 10 mA cm-2. The rechargeable liquid zinc-air battery based on Pt/C-FeNi-LDH/CA catalyst has higher open-circuit voltage (1.543 V) and galvanostatic discharge capacity at 1.23 V (830 min, 10 mA cm-2). Moreover, the zinc-air battery based on Pt/C-FeNi-LDH/CA has a small charge-discharge voltage gap (0.65 V) at 10 mA cm-2, after 200 consecutive cycles (66 h), the charge-discharge voltage gap only increased by about 30 mV, indicating good cycling stability.

Flexible Thermoelectric Wearable Architecture for Wireless Continuous Physiological Monitoring.

Continuous monitoring of physiological signals from the human body is critical in health monitoring, disease diagnosis, and therapeutics. Despite the needs, the existing wearable medical devices rely on either bulky wired systems or battery-powered devices needing frequent recharging. Here, we introduce a wearable, self-powered, thermoelectric flexible system architecture for wireless portable monitoring of physiological signals without recharging batteries. This system harvests an exceptionally high open circuit voltage of 175-180 mV from the human body, powering the wireless wearable bioelectronics to detect electrophysiological signals on the skin continuously. The thermoelectric system shows long-term stability in performance for 7 days with stable power management. Integrating screen printing, laser micromachining, and soft packaging technologies enables a multilayered, soft, wearable device to be mounted on any body part. The demonstration of the self-sustainable wearable system for detecting electromyograms and electrocardiograms captures the potential of the platform technology to offer various opportunities for continuous monitoring of biosignals, remote health monitoring, and automated disease diagnosis.

Lead-Chelating Intermediate for Air-Processed Phase-Pure FAPbI3 Perovskite Solar Cells.

Formamidinium-lead triiodide (FAPbI3) perovskite holds promise as a prime candidate in the realm of perovskite photovoltaics. However, the photo-active α-FAPbI3 phase, existing as a metastable state, is observable solely at elevated temperatures and is susceptible to degradation into the δ-phase in ambient air. Therefore, the attainment of phase-stable α-FAPbI3 in ambient conditions has become a crucial objective in perovskite research. Here, we proposed an efficient conversion process of PbI2 into the α-FAPbI3 perovskites in ambient air. This conversion was facilitated by the introduction of chelating molecules, which interacted with PbI2 to form an intermediate phase. Due to the reduced formation barrier resulting from the altered reaction pathway, this stable intermediate phase transitioned directly into α-FAPbI3 upon the deposition of the organic cation solution, effectively bypassing the formation of δ-FAPbI3. Consequently, the ambient-fabricated FAPbI3 perovskite solar cells (PSCs) exhibited an outstanding power conversion efficiency of 25.08 %, along with a high open-circuit voltage of 1.19 V. Furthermore, the unencapsulated devices demonstrated remarkable environmental stability. Notably, this innovative approach promises broad applicability across various chelating molecules, opening new avenues for further progress in the ambient air fabrication of FAPbI3 PSCs.

Interface band alignment engineering of ZnO/Si heterojunction solar cells with high open circuit voltage

Interface band alignment engineering of ZnO/Si heterojunction solar cells with high open circuit voltage

Chemical polishing strategies to improve flexible perovskite solar cells based on dopant-free hole transport layers

For n-i-p typed flexible perovskite solar cells (fPSCs), the doped hole transport layer significantly impacts the devices' long-term stability. Using dopant-free organic hole transport materials (d-HTMs) is promising for stable fPSCs. However, the low conductivity of d-HTMs limited their thickness, making them sensitive to the surface morphology of the perovskite film's upper surface. Here, we report a chemical polishing strategy using 1-hexyl-3-methylimidazolium acetate (HMIM∙Ac) as the polishing reagent to enhance the upper surface of the perovskite film, which could form a smooth and flat surface. Meanwhile, the treatment can reduce surface defects and smaller grains on top of the surface. Then, we deposite an ultra-thin dopant-free PM6 layer, a typical hole transport layer, on top of the polished perovskite film. The PM6 layer shows an improved face-on orientation and then carrier mobility. Moreover, suppressed non-radiative recombination at the perovskite/PM6 interface is also observed, translating into a higher open-circuit voltage and fill factor of the fPSCs. As a result, a champion power conversion efficiency (PCE) of 17.76 ​%, with an open-circuit voltage of 1.025 ​V and fill factor of 78.2 ​%, is obtained, which is one of the highest PCEs among the reported fPSCs based on d-HTMs. Our strategy demonstrates a facile but effective way of developing high-efficiency and stable fPSCs for future applications.

M–Nx–C (M = Fe, Zn) bi-active sites booting oxygen reduction reaction and zinc-air battery performance

Fe/N/C is recognized promising catalyst for oxygen reduction reaction (ORR), playing a pivotal role in advancing the commercialization of proton exchange membrane fuel cells. However, an inadequate ORR activity hinders its potential applications. Here, we present the preparation of M–Nx–C (M = Fe, Zn) bi-active sites for promoting ORR. By the pyrolysis of benzimidazole salts, a porous coin-like iron-zinc-based nitrogen-doped carbon materials (FeZn-NC) catalyst was synthesized with abundant active sites. X-ray photoelectron spectroscopy and transmission electron microscopy characterizations indicated the successful doping of Zn and Fe within the carbon framework. Electrochemical measurements demonstrated great positive half-wave potential (0.90 V), high limiting current density (5.15 mA·cm−2), excellent methanol resistance, and good stability of FeZn-NC, compared to commercial Pt/C catalysts. Furthermore, an investigation into correlation between doping content of Fe and the ORR performance was carried out. As an cathode catalyst of zinc-air battery, FeZn-NC exhibited more significant advantages, including a high open-circuit voltage (1.54 V), enhanced power density (199.89 mW·cm−2), good specific capacity (771.9 mAh gZn−1), and enhanced stability compared to Pt/C. By presenting an approach for the controlled synthesis of metal-doped carbon materials, this work establishes the groundwork for potential applications in catalytic fields, as demonstrated by the prepared FeZn-NC.

Efficient perovskite solar cells based on polyoxyethylene bis(amine) and NaPF6 modified SnO2 layer with high open-circuit voltage

The electron transport layer (ETL) of SnO2 with a rough surface, low conductivity, and poor wettability has limited its application in perovskite solar cells (PSCs). To address this issue, we propose a strategy that involves the simultaneous use of bulk dopant NaPF6 and polymer stabilizer NH2-PEG-NH2 in SnO2. NH2-PEG-NH2 is compatible with both SnO2 and NaPF6, resulting in a homogeneous distribution. Additionally, the intrinsic hydrophilicity of the polymer facilitates the formation of a continuous and ordered ETL with improved wettability. The inclusion of NaPF6 as a bulk dopant enhances conductivity and promotes upper perovskite growth. As a result, optimized morphology, aligned energy levels, improved crystallinity, and reduced bottom defects are achieved in the fabricated perovskite layer. The champion device exhibits a power conversion efficiency (PCE) of ∼23.36%, which is ∼11.88% higher than that of the pristine device (PCE = 20.88%). Notably, the VOC reaches ∼1.2 V with only ∼0.08 V of VOC loss, which is among the highest report one. Furthermore, the PCE of the modified unpackaged PSC was only attenuated by 25% after 250 h of maximum power point tracking in the environment. These results present an alternative and effective approach for preparing high-quality SnO2 ETL for efficient PSCs.

Epitaxial Growth of Two-Dimensional MoO2-MoSe2 Metal-Semiconductor Heterostructures for Schottky Diodes.

The metal-semiconductor interface fabricated by conventional methods often suffers from contamination, degrading transport performance. Herein, we propose a one-pot chemical vapor deposition (CVD) process to create a two-dimensional (2D) MoO2-MoSe2 heterostructure by growing MoO2 seeds under a hydrogen environment, followed by depositing MoSe2 on the surface and periphery. The ultraclean interface is verified by cross-sectional scanning transmission electron microscopy and photoluminescence. Along with the high work function of semimetallic MoO2 (Ef = -5.6 eV), a high-rectification Schottky diode is fabricated based on this heterostructure. Furthermore, the Schottky diode exhibits an excellent photovoltaic effect with a high open-circuit voltage of 0.26 eV and ultrafast photoresponse, owing to the naturally formed metal-semiconductor contact with suppressed pinning effect. Our method paves the way for the fabrication of an ultraclean 2D metal-semiconductor interface, without defects or contamination, offering promising prospects for future nanoelectronics.

Enhanced efficiency of bifacial perovskite solar cells using computational study

The most rapidly expanding type of solar cells are the Perovskite Solar Cells (PSCs), because of its high device performance, ease of synthesis, high open-circuit voltage, and affordability. Despite these advantages, the development of perovskite-based solar cells continues to be impeded by the issues with perovskite stability and the utilization of the hazardous heavy element lead (Pb). The study emphasizes on the bifacial structure that maintains the conventional absorber layer and electron transport layer (ETL) in the optimized PSC structure. This study employs SCAPS software for device simulation to comprehensively analyze how various parameters affect the performance of solar cells. Additionally, doping concentration variation in both ETL and HTL are explored. The simulation reveals that changing device structure from monofacial to bifacial significantly influences PSC performance, demonstrating that optimizing individual layers effectively enhances overall solar cell performance. The optimized structure achieves impressive PSC performance metrics through parametric analysis, such as voltage (VOC) of 1.18 V, fill factor (FF) of 82.24%, current density (JSC) of 27.12 mA/cm2, power conversion efficiency (PCE) of 27.90% for an incident solar spectrum from the ETL side, and power conversion efficiency (PCE) of 19.86% for an incident solar spectrum from the HTL side, the calculated bifaciality factor (BF) for this structure is 71.18%.

Performance test and prediction on a radial π-type annular thermoelectric generator directly exposed to an automotive pipe for waste heat recovery

The application of annular thermoelectric generators (ATEGs) in waste heat recovery from automobile exhausts is promising. Directly exposing ATEGs to an automotive exhaust pipe avoids using a heat exchanger to extract heat and therefore enhances the system efficiency. However, to the best of the authors’ knowledge, such a test has not been experimentally done before. In this study, for the first time, we fabricated a radial π-type ATEG that comprised 30 thermoelectric units and tested the output performance when it was exposed to an exhaust pipe. We then constructed a numerical model to explore the best-performing conditions for the ATEG. Finally, a high-efficiency ATEG-based power generator was designed and the output characteristics were predicted under practical vehicle-running conditions. We found that the manmade ATEG performed well and generated an open-circuit voltage (OCV) of 231.77 mV under a temperature difference of 25.5 °C. Numerical modeling showed that the designed 4 cm long power generator (240 thermoelectric units), directly installed to an automotive exhaust pipe where the gas temperature approached 500 °C, attained an OCV of 19.64 V and a conversion efficiency of 9.6 % when the average velocity of the vehicle was 65 km/h (atmospheric temperature at 25 °C); Higher OCV and efficiency are expected when the car runs faster. Besides, a maximum OCV of 24.18 V and an efficiency of 11.9 % were achieved in the presence of water (at 25 °C) as the cooling medium and at a velocity of 1 m/s. The well-performed radial π-type ATEG could be easily made and installed. This study provides experimental evidence of ATEG having the potential to efficiently recover automotive waste heat by being directly exposed to the exhaust pipe and greatly facilitates the practical application of ATEGs.

Controllable construction of CoP nanoparticles anchored on a nitrogen-doped porous carbon as an electrocatalyst for highly efficient oxygen reduction in Zn-air batteries

Exploring cost-efficient and highly-efficient noble metal-free catalysts for the oxygen reduction reactions (ORRs) involved in sustainable energy devices remains a great challenge. Transition-metal phosphides supported on heteroatom-doped carbons have shown potential as alternative candidates for precious metals because of their tunable electronic structures and higher catalytic performance. Phosphating was used to construct CoP nanoparticles (NPs) anchored on a nitrogen-doped porous carbon framework (CoP@NC) from Co NPs loaded on NC, using PH3 gas released from NaH2PO2 during heat treatment. The dodecahedral structure of Co NPs was retained in their transformation to CoP NPs. The CoP@NC electrocatalyst shows a remarkable ORR activity with a half-wave potential up to 0.92 V under alkaline conditions, which is attributed to the combined coupling between the well dispersed CoP nanoparticles on the nitrogen-doped carbon and the efficient mass transport in the porous structure. Zinc-air batteries assembled with the CoP@NC electrocatalyst as a cathode have a high open-circuit voltage of 1.51 V and power density of 210.1 mW cm−2. This work provides a novel strategy to develop low-cost catalysts with an excellent ORR performance to promote their practical use in metal-air batteries

Effect of ball milling energy and carbon content on electrochemical properties of FeF3/acetylene black composites for high-capacity thermal battery

Recently, there has been an increasing demand for high-voltage thermal batteries. FeF3 has a high open-circuit voltage of 2.7 V and is gaining attention as a potential alternative. However, it involves the problem of a low electrical conductivity owing to the wide band gap (5.96 eV) and the generation of lithium fluoride (LiF), which is a discharge product in the conversion reaction. To address this issue, acetylene black with high conductivity is utilized to enhance the electrochemical activity of metal fluoride (FeF3). At present, FeF3/AB is produced by low- and high-collision-energy ball milling. These are mechanical milling methods that involve different collision energies. High-collision-energy ball milling has been demonstrated to degrade the electrochemical performance owing to crystal deformation. In contrast, low-collision-energy ball milling has demonstrated the potential for application in thermal batteries by minimizing crystal deformation and enhancing the electrical conductivity. In this study, the amount of added carbon was optimized to enhance the performance of thermal battery materials. Both low- and high-collision-energy ball-milling processes exhibited remarkable thermal stability when 5.0 wt% carbon was added. However, the high-collision-energy ball-milling process did not effectively enhance the thermal cell performance because the electrical conductivity did not increase significantly. Therefore, FeF3/5.0 wt% AB produced by low-collision-energy ball milling exhibited remarkable thermal stability and electrical conductivity. This indicates its potential for use in thermal batteries.

Boosting borohydride oxidation kinetics by manipulating hydrogen evolution and oxidation through octahedral Pt–Ni/C for high-performance direct borohydride fuel cells

Direct borohydride fuel cells (DBFCs) outperform the other direct liquid fuel cells by a higher open circuit voltage and energy density. However, their benign performance and efficiency are highly dependent on high-performance anode catalysts. This study delves into the enhancement of borohydride oxidation reaction (BOR) kinetics through an octahedral Pt–Ni/C catalyst. The Pt(111) facets of the catalyst exhibit a combination of abundant active sites exposed for BOR and the inherent ability to suppress hydrolysis reaction. Furthermore, the synergistic incorporation of Ni modifies the electronic structure of Pt, resulting in enhanced OH− adsorption and hydrogen oxidation reaction (HOR) activity. This multifaceted approach not only mitigates hydrogen accumulation but also boosts the overall BOR efficiency. The elaborate electrochemical measurements along with comprehensive characterizations elucidate the superior catalytic activity and stability of Pt–Ni/C over commercial Pt/C catalysts. Specifically, DBFCs employing the Pt–Ni/C catalyst manifest considerably higher open circuit voltage (1.05 V), peak power density (1.82 W cm−2) and fuel efficiency (63.96 %) than those of DBFCs employing Pt/C catalyst. Through these efforts, we provide significant insight into the design of high-performance anode catalyst for DBFCs.

Double-skeleton interpenetrating network-structured alkaline solid-state electrolyte enables flexible zinc-air batteries with enhanced power density and long-term cycle life

The alkaline solid-state electrolytes have received widespread attention for their good safety and electrochemical stability. However, they still suffer from low conductivity and poor mechanical properties. Herein, we report the synthesis of double-network featured hydroxide-conductive membranes fabricated by polyvinyl alcohol (PVA) and chitosan (CS) as the double-skeletons. Then, we implanted quaternary ammonium salt guar hydroxypropyltrimonium chloride (GG) as the OH− conductor for high-performance electrochemical devices. By virtue of the unique stripe-like structure shared from the double skeleton with a high degree of compatibility and stronger hydrogen bond interactions, the polyvinyl alcohol/chitosan-guar hydroxypropyltrimonium chloride (PCG) solid-state electrolytes achieved optimal thermal stability (> 300 °C), mechanical property (∼ 34.15 MPa), dimensional stability (at any bending angle), and high ionic conductivity (13 mS cm−1) and ion mobility number (tion ∼ 0.90) compared with chitosan-guar hydroxypropyltrimonium chloride (CG) and polyvinyl alcohol-guar hydroxypropyltrimonium chloride (PG) electrolyte membrane. As a proof-of-concept application, the “sandwich”-type zinc-air battery (ZAB) assembled using PCG membrane as the electrolyte realized a high open-circuit voltage (1.39 V) and an excellent power density (128 mW cm−2). Notably, in addition to its long-term cycle life (30 h, 2 mA cm−2) and stable discharge plateau (12 h, 5 mA cm−2), it could even enable a flexible ZAB (F-ZAB) to readily power light-emitting diodes (LED) at any bending angle. These merits afford the PCG membrane a promising electrolyte for improving the performance of solid-state batteries.

Low-humidity sensor and biomimetic power supply based on mesoporous silica/polymerizable deep eutectic solvent ionogels

Although technologies related to humidity detection and utilization, such as humidity sensors, atmospheric water harvesting, energy collection, and moisture-enabled electrical generation technologies, have been widely reported, there is still an urgent need for effective monitoring and utilization of humidity in low-humidity places. An ideal low-humidity sensor requires a high response, fast response time and low humidity hysteresis. Soft ion power supplies inspired by electric eels convert the chemical potential energy of ion gradients into electrical energy by utilizing humidity, but their production is challenging. This paper reports a new strategy for developing functionalized ionogels based on mesoporous silica and a polymerizable deep eutectic solvent (SiO2@PDES). Due to their strong hydrophilicity, high ionic conductivity, excellent adhesion, flexibility and mechanical strength, SiO2@PDES ionogels can not only detect low humidity but also generate electric power through a reasonably designed device structure. In the 5–30% RH range, the response of the SiO2@PDES humidity sensor reaches 1600%, with negligible humidity hysteresis (0.8% RH). As a biomimetic soft ion power supply, SiO2@PDES ionogels generate a high open-circuit voltage of ∼600 mV at 33% RH, which expands the environmental adaptability of moisture-enabled electrical generation equipment. In addition, the excellent moisture-enabled electrical generation performance endows portable wearable power supplies with high potential for applications such as charging capacitors and lighting LEDs.