Interfacial Electric Field Research Articles

Oxygen-Defective Bi2MoO6/g-C3N4 hollow tubulars S-scheme heterojunctions toward optimized photocatalytic performance

Novel S-scheme heterojunction photocatalysts of bismuth molybdate/hollow tube graphite carbon nitride (Bi2MoO6 SOVs/g-C3N4) containing surface defects (SOVs) were prepared by calcination and hydrothermal methods. The hollow tubular structure of g-C3N4 facilitates the enhancement of multiple reflection and scattering of light, and also have a larger range of specific surface areas and more reactive sites, which promotes carrier separation and thus improves photocatalytic performance. The introduction of SOVs to bismuth molybdate not only reduces the band gap of bismuth molybdate, but also promotes the separation of charges. The optimized Bi2MoO6 SOVs/TCN photocatalyst has a hydrogen production efficiency of 2.29 mmol h−1 g−1. It also shows high photocatalytic degradation property of tetracycline and bisphenol A in water, up to 97.3 % and 98.9 %, respectively. Meanwhile, the transfer mechanism of photogenerated charges in S-scheme heterojunctions can be verified by electron paramagnetic resonance and in situ irradiated x-ray photoelectron spectroscopy electron paramagnetic resonance, which accelerated the separation and transfer of photogenerated charge by energy band bending at the interface and internal electric field. This rational structural design strategy provides a new development idea for building high-performance S-scheme heterojunction photocatalysts.

Construction of interfacial electric field via Bimetallic Mo2Ti2C3 QDs/g-C3N4 heterojunction achieves efficient photocatalytic hydrogen evolution

Exploiting photocatalysts with high interfacial charge separation efficiency remains a huge challenge for converting solar energy into chemical energy. Herein, a novel 0D/2D heterojunction is successfully constructed by using bimetallic Mo2Ti2C3 MXene Quantum Dots (Mo2Ti2C3 QDs) firmly immobilized on the surface of g-C3N4 nanosheet via an electrostatic self-assembly strategy. The Mo2Ti2C3 QDs/g-C3N4 exhibits an efficient and stable photocatalytic hydrogen production performance up to 2809 µmol g-1h−1, which is 7.96 times higher than pure g-C3N4 nanosheet, and prominently exceeding many reported photocatalysts. Besides, a prominent apparent quantum yield achieves 3.8% at 420 nm. The significant performance improvement derives from the giant interfacial electric field that formed between large interface contact areas, ensuring greatly efficient separation and transfer of the photogenerated carriers. Furthermore, the 0D/2D heterojunction possesses high-quality interfacial contact, which reduces the interfacial recombination of photoinduced electrons and holes, causing the quick electron transfer from the g-C3N4 to electron acceptor Mo2Ti2C3 QDs, thus enhancing the charge utilization. Kelvin probe force microscopy (KPFM) measurements and density functional theory (DFT) calculation comprehensively demonstrate that g-C3N4 modified by Mo2Ti2C3 QDs can modulate the electronic structure and prompt the establishment of the interfacial electric field, which consequently leads to efficient photocatalytic activity. This study adequately illustrates that constructing heterojunction interfacial electric fields based on MXene quantum dots is a prospective pathway to engineering high-performance photocatalytic platforms for solar energy conversion.

Highly Reversible Zinc‐Air Batteries at −40 °C Enabled by Anion‐Mediated Biomimetic Fat

AbstractThe wide application of portable electrical equipment, aerial vehicles, smart robotics, etc. has boosted the development of advanced batteries with safety, high energy density, and environmental adaptability. Inspired by the fat layer on animal bodies, biomimetic fat is constructed as electrolytes of solid‐state zinc‐air batteries to achieve excellent cycling performance at low temperatures. Via tailored anion‐H2O interaction, the antifreezing gel electrolytes, with the multi‐performance of interface compatibility, temperature adaptability, and stable power supply simultaneously, build robust Zn|electrolyte interface, thus promoting uniform interfacial electric fields and Zn deposition. Excellent long‐term cyclability of 120 h at a high current density of 50 mA cm−2 are exhibited at 25 °C. Moreover, at −40 °C, a record‐long cycling life of 205 h at a current density as large as 10 mA cm−2 is achieved.

Gapless linear dispersion in Bi2Se3 nanoparticles for high-performance broadband photodetectors

Topological insulators have demonstrated novel optoelectronic properties owing to their gapless linear dispersion and robust surface states. In this study, we implemented high-performance broadband photodetectors based on mixed-dimensional heterostructure of the topological insulator Bi2Se3 nanoparticles (NPs) with the semiconductor WSe2. Prominently, the Bi2Se3 NPs/WSe2 structure exhibited photoresponsivity of 22.17 A/W in the visible (Vis) wavelengths, and 5 A/W in the near-infrared (NIR) wavelengths and a fast response time of 40 μs. In comparison with typical semiconducting PbS NPs/WSe2 structure, we confirmed that the enhancement in the photoresponsivity, response time, and broadband photoresponse of the Bi2Se3 NPs/WSe2 structure can be attributed to the gapless behavior in surface states of topological insulator materials. Numerical simulations also confirmed a dramatic increase in the interfacial electric field by two orders of magnitude, resulting from the surface states in topological insulator NPs. The observed experimental results and the proposed mechanism pave the way for the emergence of efficient optoelectronic devices based on topological insulator materials.

Photocatalytic nitrogen fixation by g-C3N4/MoS2/PbTiO3 with synergistic electric field

Photocatalytic nitrogen fixation under mild conditions is considered to be one of the interesting and challenging approaches to relieve energy scarcity. In this work, g-C3N4/MoS2/PbTiO3 composites are successfully designed and synthesized for photocatalytic nitrogen fixation. The interfacial electric field of S-scheme heterojunction, the polarization electric field inside PbTiO3, and the bound electric field induced by the polarized electric field synergistically construct the synergistic electric field in g-C3N4/MoS2/PbTiO3 under ultrasonic vibration. Under the effect of synergistic electric field, honeycomb structure, and nitrogen defects, the yield of photocatalytic nitrogen fixation by g-C3N4/MoS2/PbTiO3 reaches 6288 μmol·L−1·g−1·h−1, which is 6.58, 3.61, and 2.37 times that of PbTiO3, MoS2, and g-C3N4, respectively. The synergistic electric field offers a sufficient driving force for photogenerated carrier separation and migration. And the honeycomb structure and nitrogen defects provide sufficient reaction sites for photocatalytic nitrogen fixation. This work offers some insights for developing efficient ferroelectric-based photocatalysts.

Temperature‐Dependent Photoredox Catalysis for CO2 Reduction Coupled with Selective Benzyl Alcohol Oxidation over ZnIn2S4/In2O3 Heterostructure

CO2 reduction (CO2RR) with selective benzyl alcohol (BA) oxidation in a single photoredox reaction can simultaneously utilize photogenerated electrons and holes to realize efficient production of fuels and value‐added chemicals. Herein, a unique 2D/1D ZnIn2S4/In2O3 (ZIS/In2O3) heterostructure is developed displaying outstanding performance for photoredox catalysis. As is unequivocally illustrated by various advanced ex situ/in situ characterizations and theoretic calculations, the notable catalytic performances originate from the built‐in interfacial electric field within the ZIS/In2O3 heterostructure, which strongly ameliorates the separation and transport of charge carriers. Remarkably, the catalytic activity can further be boosted after coupling the additional thermal treatments, and the product selectivity is highly temperature dependent. Thereby, the precise formation of targeted products, which can serve as valuable industrial products and fuels can be controlled by changing the reaction temperatures, including obtaining the syngas with different H2/CO ratios from CO2 reduction, as well as benzaldehyde, hydrogenated benzoin, and dibenzyl ether (never reported for BA during photocatalysis) from the BA conversion. This study offers a constructive and inspiring contribution to reasonably developing photoredox catalysts, which can fully utilize photogenerated electrons and holes, as well as demonstrate how to controllably yield the targeted products by coupling thermo‐ and photoredox catalysis.

Self‐Smoothing Deposition Behavior Enabled by Beneficial Potential Compensating for Highly Reversible Zn‐Metal Anodes

AbstractRealizing compact dendrite‐free zinc (Zn) plating is crucial to avoiding premature battery failure caused by internal short‐circuits, which is highly determined by the interface electric field (ψi) distribution. Herein, a concept of “potential compensating” is shown on Zn anodes to stimulate its self‐smoothing deposition behavior for durable batteries. A homogeneous ψi with elevated potential intensity is successfully built at the Zn/electrolyte interface via the selective adsorption of highly polarized propylene glycol (PG) molecules, which facilitate the formation of dense and uniform Zn electroplating patterns. Moreover, the PG additive can simultaneously reshape the structure of Zn2+‐solvation sheath and immobilize the H‐bonding networks in bulk electrolyte, enabling Zn anodes with exceptional electrochemical reversibility (99.6%) and ultralong calendar life (3500 h), as revealed by joint spectroscopic and electrochemical analyses. More importantly, full cells with PG safeguard can deliver desirable cycling stability even at an elevated temperature (50 °C) and low N/P ratios (cathode mass loading up to 14.38 mg cm−2). This study presents new insight into the rational design of stable practical electrolytes and interfacial chemistry regulation for sustainable zinc batteries.

In-situ construction of S-scheme (BiO)2CO3/TiO2 heterojunctions with enriched oxygen vacancies and enhanced photocatalytic performance

Solar energy is a sustainable, green, and clean energy source among all the energy sources. Photocatalytic degradation with the aid of solar energy has been the theme of wastewater treatment. In this work, (BiO)2CO3 (BOC) was synthesized on the surface of TiO2 in alkaline environment (pH = 10.0) using bismuth nitrate pentahydrate as the bismuth source and urea as the carbon source, thus S-scheme BOC/TiO2 heterojunctions were successfully in-situ constructed. The experimental consequences demonstrate that formation of BOC/TiO2 heterojunctions can induce rich surface OVs and generate a strong interfacial electric field between BOC and TiO2, which leads to the directional movement of photoinduced e−/h+ pairs. The effective segregation of photoexcited e−/h+ pairs can be attained by the collaborative action of surface OVs and the spatial electric field. After irradiation by a Xenon lamp for 60 min, the BOC/TiO2-3 sample accomplishes a decontamination efficiency of 98% and 97.5% for rhodamine B (RhB) and ciprofloxacin (CIP), respectively. Furthermore, the disintegration rate constant of RhB and CIP on the catalyst is 3.6-fold and 0.9-fold higher than that on the reference TiO2, respectively. According to the observations, segregation and migration of the carriers follows a S-scheme mechanism.

Engineering a Ni-Al Brucite-Based Interface Layer with Regulated Zn2+ Flux for Highly Reversible Zn Metal Anodes.

Practical aqueous Zn-ion batteries are appealing for grid-scale energy storage with intrinsic safety and cost-effectiveness, yet their cycling stability and reversibility are limited by unwanted dendrite growth and water-induced erosions on Zn. Herein, a hydrophilic and Zn2+-conductive Ni-Al layered double hydroxide (NiAl-LDH) interphase layer is constructed on the surface of Zn, in which NiAl-LDH enables a more uniformly distributed Zn2+ concentration and interfacial electric field owing to its large internal Zn2+ channels and favorable charge redistribution effect. Consequently, the NiAl-LDH-integrated Zn anode achieves low voltage hysteresis and high reversibility of Zn plating/stripping with uniform underneath deposition behaviors. Remarkably, the resultant NiAl-2 LDH@Zn delivers superior cycling durability over 2800 h (∼4 months, 0.5 mA cm-2), realizes high reversibility with 99.4% average Coulombic efficiency over 1400 cycles, and confers stable operation of full Zn cells with high V2O5 mass loadings. This work offers a facile and instructive interface design approach for achieving highly stable Zn metal anodes.

Multilevel Heterostructure of MoS2/GDYO for Lithium‐Ion Batteries

AbstractLayered guest carbon materials could induce interlayer engineering, especially in regulating the interlayer structure and electronic properties of the hosts, leading to high performance in Li‐ion batteries (LIBs). Here, crystalline graphdiyne oxide (GDYO) is successfully inserted into MoS2 gallery via electrostatic self‐assembly. Experimental and theoretical data show that GDYO‐embedding induces interlayer engineering of MoS2 causing (i) enlarged MoS2 interlayer distance (supplying additional Li‐ion diffusion channels and storage sites and mitigating volume change), (ii) creating interfacial electric fields (significantly improving Li‐ion transport kinetics), (iii) limiting the electrochemical products of Mo and soluble lithium polysulfide (MoS2 structure regeneration), and (iv) regulation of the interfacial current density distribution during the electrochemical reaction (uniform Li plating). Moreover, through systematic ex situ and in situ investigations, the triple‐mechanism of Li‐ion storage is thoroughly elucidated in the heterostructure, emphasizing the positive effects of GDYO intercalation on the interfacial and interlayer storage as well as the phase conversion processes. Such a MoS2/GDYO anode exhibits high reversible capacity (≈652.6 mAh g−1 at 2.0 A g−1) and superior cyclic stability of 655.1 mAh g−1 after 1000 cycles. GDYO‐induced interlayer engineering based on host–guest chemistry can provide new ideas for designing effective heterostructures for high‐performance energy storage and conversion systems.

Boosting photoelectrochemical performance of CuFeO2/CuO photocathode by modulating heterojunction architecture and oxygen vacancies

This study aims to enhance the PEC properties of CuFeO2 nanosheets by constructing closely bonded CuFeO2/CuO heterostructures. CuO crystal-structured films were prepared using the sol-gel spin-coating method, wherein the annealing temperature was varied to modulate the content of oxygen vacancies. Compared to pristine CuFeO2 and two tandem architectures, the CuFeO2@VO-CuO core-shell architecture outperformed by yielding a photocurrent density of 68 μA/cm2, which marks an almost 8.5, 1.36 and 2.27 times enhancement. Experimental results verified solid atomic-level contact bonding at the CuFeO2@VO-CuO junction, thereby augmenting overall efficiency. Through the optimized fabrication process of the CuFeO2@VO-CuO core-shell heterostructure, carrier concentration and transport and electron-hole pair separation saw substantial improvement, further boosting its PEC performance. Critically, the presence of oxygen vacancies in the CuFeO2@VO-CuO heterostructure played a pivotal role. Oxygen vacancies eliminated potential traps for captured electrons at the interface and suppressed the formation of unoccupied interface states, reducing recombination of photogenerated electron-hole pairs. Moreover, oxygen vacancies facilitated conduction band alignment, promoting efficient separation and rapid transfer of photogenerated electron-hole pairs. In conclusion, the CuFeO2@VO-CuO core-shell heterostructure achieves efficient separation and transfer of photogenerated electron-hole pairs while effectively suppressing recombination, thanks to the synergy between the interfacial electric field and oxygen vacancies.

Co-modulated interface binding energy and electric field distribution of layer-structured PVDF-LDPE dielectric composites with BaTiO3: experiment and multiscale simulations

Co-modulated interface binding energy and electric field distribution of layer-structured PVDF-LDPE dielectric composites with BaTiO3: experiment and multiscale simulations

Lithiophilic Zn3N2-Modified Cu Current Collectors by a Novel FCVA Technology for Stable Anode-Free Lithium Metal Batteries.

Anode-free lithium metal batteries (AFLMBs) offer high-energy-density battery systems, but their commercial viability is hindered by irregular lithium dendrite growth and "dead Li" formation caused by current collector defects. This study employed filtered cathode vacuum arc (FCVA) technology to fabricate Cu current collectors (CCs) with a lithiophilic Zn3N2 film. This advanced preparation process ensures an evenly distributed film that reduces the nucleation overpotential, homogenizes the interfacial electric field during plating/stripping processes, inhibits lithium dendrite growth, and forms a stable solid-electrolyte interphase (SEI). Our results show that the advanced Zn3N2@Cu CCs exhibit superior performance with a high CE of above 99.3% after 230 cycles at a current density of 0.5 mA cm-2 and an area capacity of 1 mAh cm-2. Additionally, Li-Zn3N2@Cu||Li-Zn3N2@Cu symmetrical cells had a longer stable cycle time of over 1000 h than that of Li||Li and Li-Cu||Li-Cu symmetrical cells at a current density of 1 mA cm-2 and an area capacity of 2 mAh cm-2. Compared with bare Cu CCs, the capacity retention rate is increased from 14.9 to 63.1% after 100 cycles with a 0.5C rate in the AFLMBs with LFP as the cathode. This work provides a pioneering, eco-friendly, and effective solution for the fabrication of anode CCs in AFLMBs, addressing a significant challenge in their commercial application.

(Invited) Cations at a Solid-Liquid Interface: A Second Harmonic Generation Investigation

When an electrode contacts an electrolyte, an interfacial electric field forms. This interfacial field can polarize the electrode’s surface and nearby molecules, but its effect can be reversed by applying external potential. One method for quantifying this effect is the phase-sensitive second harmonic generation (PS-SHG) technique. We present our PS-SHG investigation of the Pt/water interface, where we examine the impact of the electrolyte chemistry on the electrical double layer (EDL). We will discuss how switching cations in alkaline electrolytes can affect the solid-liquid interface, in particular, the behavior of interfacial water. Our work provides a tool for quantifying the interfacial electric field at an electrode-electrolyte interface and shows the possibility of how cations can modify the EDL.

(Invited) Towards a Mechanistic Understanding of the Oxygen Evolution Reaction on Hematite: Operando Characterization of Band Bending and Interfacial Chemical Speciation Using Sum Frequency Generation Spectroscopy

Hematite is an attractive photoanode for the oxygen evolution reaction (OER) due to its cheap price, relatively small band gap, stability in alkaline solution and a valence band energy suitable for OER catalysis. However, insight into the OER mechanism, and thus the capability to rationally modify this material to optimize performance, is limited by the challenge in relating band bending, surface state population and chemical reactivity operando. Conventionally these issues are addressed by some combination of electrochemical impedance spectroscopy (EIS), photocurrent/voltage kinetics, and linear optical spectroscopies in the visible. While important, all of these approaches suffer from significant limitations: e.g. EIS and related techniques integrate over all charge transfer processes in the device while only those at the hematite/water interface are of interest (and thus require a challenging to validate model to quantify) and UV/Vis absorption measurements (whether steady-state or time resolved) are bulk-sensitive and probe spectrally broad features that are challenging to relate to surface structure.Sum Frequency Generation (SFG) spectroscopy is interface-specific by its symmetry selection rules, can straightforwardly probe interfacial chemical speciation if one of the two incident fields is in the infrared, and is sensitive to the amplitude of interfacial electric fields. These attributes make the technique particularly suitable for characterization of interfacial chemical speciation, double layer and space charge layer structure at the working electrode/electrolyte interface within thin-film spectroelectrochemical cells. Here I describe our recent efforts to characterize chemical speciation and interfacial field at a hematite/electrolyte interface, in the presence and absence of external illumination, as one moves from the Hematite flat band potential through the onset of the OER. Using vibrationally resonant SFG spectroscopy, at infrared wavelengths > 10 micron, we quantify the population of surface holes, i.e. Fe(IV)=0 groups, as the OER turns on. Concurrently we quantify the development of the space charge potential using non-resonant SFG. Recent work has argued, largely from current or optical transients in the visible under chopped illumination, that the OER on Hematite proceeds by a multi-hole mechanism. Because our approach allows for the simultaneous quantification of interfacial field and chemical speciation we directly address this mechanism and the circumstances under which it is expected to apply. More generally, the role of interfacial field in oxidation catalysis has been an object of much current interest. The approach described here – in which interfacial speciation and field can be quantified operando – offers an ability to explore this relationship not possible via any other combination of experimental approaches.

Understanding Water Dissociation in Bipolar Membranes for Applications in CO2 Electrolyzers

Bipolar membranes (BPMs) offer a unique way to manage local pH and control ion crossover in diverse devices for electrodialysis, water and CO2 electrolysis, and for water purification and metals recycling. Current commercial BPMs, however, are limited to low current densities and with low energy efficiencies. The water dissociation (WD, H2O → H+ + OH−) reaction under reverse bias, is the core process in BPMs that limits efficiency. A deeper understanding of WD in BPMs, and improving the WD rate, will enable broad use of BPMs in novel CO2 electrolyzers designs. Both electric-field and catalytic effects have been invoked to describe WD, but the interplay of the two and the underlying design principles for WD catalysts remain unclear. Using precise layers of metal-oxide nanoparticles, membrane-electrolyzer platforms, materials characterization, and impedance analysis, we illustrate the role of electronic conductivity in modulating the performance of WD catalysts in the BPM junction through screening and focusing the interfacial electric field. BPM electrolyzers, optimized via these findings, use ~30-nm-diameter anatase TiO2 as an earth-abundant WD catalyst, and generate O2 and H2 at 500 mA cm−2 with a record-low total cell voltage below 2 V. Furthermore, integrating reference electrodes into electrolyzers allows the precise study of WD kinetics. Using TiO2-P25 as a model WD catalyst, we discovered an apparent activation energy of 25–30 kJ mol−1, only weakly dependent on the driving force (WD overpotential, η wd), while the pre-exponential factor is proportional to η wd. We proposed a new field-enhanced catalytic WD mechanism including the proton transport on the catalyst surface with the local electric field, which works to organize water molecules for proton transfer elementary steps comprising WD. These understandings of WD in BPMs will accelerate deployment of new electrodialysis, carbon-capture, and carbon-utilization technology.

(Keynote) Electrochemical Proton-Coupled Electron Transfer Theory

Proton-coupled electron transfer (PCET) plays a vital role in a wide range of electrochemical processes. This talk will describe theoretical and computational methods that have been developed to study electrochemical PCET and a variety of applications to molecular and heterogeneous electrocatalysis. My group has formulated a general PCET theory that includes the quantum mechanical effects of the electrons and transferring protons, as well as the motions of the donor-acceptor modes and solvent or protein environment. This PCET theory enables the calculation of rate constants and kinetic isotope effects for comparison to experiment. Our extension of this theory to electrochemical PCET incorporates the electronic structure of the electrode and the interfacial electric fields arising from the electrical double layer. Theoretical formulations for both homogeneous and heterogeneous electrochemical PCET provide analytical expressions for the rate constants and current densities as functions of applied potential. This theory has been applied to proton discharge on metal electrodes, as well as PCET at metal oxides and graphite-conjugated catalysts. These applications highlight the importance of using a theory that quantizes the transferring proton and includes the effects of hydrogen tunneling and excited electron-proton vibronic states. The insights from these theoretical studies are useful for the design of electrocatalytic systems to control the movement and coupling of electrons and protons for energy conversion processes.References Venkataraman, A. V. Soudackov, and S. Hammes-Schiffer, Theoretical formulation of nonadiabatic electrochemical proton-coupled electron transfer at metal-solution interfaces, J. Phys. Chem. C 112, 12386-12397 (2008).K. Goldsmith, Y. C. Lam, A V. Soudackov, and S. Hammes-Schiffer, Proton discharge on a gold electrode from triethylammonium in acetonitrile: Theoretical modeling of potential-dependent kinetic isotope effects, J. Am. Chem. Soc. 141, 1084-1090 (2019).C. Lam, A. V. Soudackov, and S. Hammes-Schiffer, Kinetics of proton discharge on metal electrodes: Effects of vibrational nonadiabaticity and solvent dynamics, J. Phys. Chem. Lett. 10, 5312-5217 (2019).E. Warburton, P. Hutchison, M. N. Jackson, M. L. Pegis, Y. Surendranath, and S. Hammes-Schiffer, “Interfacial field-driven proton-coupled electron transfer at graphite-conjugated organic acids,” J. Am. Chem. Soc. 142, 20855-20864 (2020).E. Warburton, A. V. Soudackov, and S. Hammes-Schiffer, Theoretical modeling of electrochemical proton-coupled electron transfer, Chem. Rev. 122, 10599-10650 (2022).

Interfacial Mediation by Sn And S Vacancies of p‐SnS/n‐ZnIn2S4 for Enhancing Photocatalytic Hydrogen Evolution with New Scheme of Type‐I Heterojunction

AbstractThe construction of interfacial electric field (IEF) in semiconductor heterojunction is of great significance in boosting photocatalytic hydrogen evolution through efficient separation of photogenerated charge‐carriers. However, the exploitation of IEF in type‐I heterojunction has not been proposed for designing photocatalysts. Herein, based on the density functional theory prediction, p‐SnS with different work functions modulated by Sn‐vacancy are compounded with n‐ZnIn2S4 containing S‐vacancy to form type‐I heterojunction. The optimized SnS/ZnIn2S4 photocatalyst without co‐catalysts exhibits an impressive hydrogen evolution rate of 22.75 mmol g−1 h−1, 6.23 times of ZnIn2S4. Systematic investigations reveal that the interfacial Sn‐S bond acts as a transport channel that accelerates the interface charge‐carriers transfer under the promotion of IEF originating from the significant Fermi level difference. A large difference in the surface photovoltage signal of SnS/ZnIn2S4 and ZnIn2S4 is achieved from effective photogenerated charge‐carriers separation by IEF. The new p‐n type‐I scheme of SnS/ZnIn2S4 induced by the interfacial mediation can separate the photogenerated charge‐carriers, and retain the highly reductive electrons of ZnIn2S4 for hydrogen evolution, overcoming the disadvantage of reduction potential decline in the typical type‐I scheme. This study will afford a new theoretical basis for the achievement of high‐efficiency photocatalytic hydrogen evolution through interface modulation.

Designing Soft Solid‐like Viscoelastic Zinc Powder Anode toward High‐Performance Aqueous Zinc‐Ion Batteries

AbstractZn powder is considered as a potential Zn metal anode for aqueous Zn‐ion batteries. However, restricted ion/electron transfer and volume effect‐caused electrical contact failure in conventional polymer binder composited Zn powder anodes deteriorate their electrochemical performance. Here, a high‐performance soft solid‐like viscoelastic Zn powder composite anode is proposed based on an oligomer gluing strategy. Benefiting from the viscoelastic properties, the soft‐solid Zn powder composite (ss‐ZnP) anode has significantly enhanced charge transfer, alleviated volume effect, and homogenized interfacial electric field, leading to fast plating/stripping kinetics and dendrite‐free deposition morphology. Furthermore, the assembled NH4V4O10‖ss‐ZnP full cell delivers higher capacity (510 mAh g−1 at 0.1A g−1, 300 mAh g−1 at 1A g−1) and longer lifespan up to 500 cycles at 1 A g−1, superior to conventional polymer binder composited Zn powder anode and other reported rheological Zn powder‐based anodes. Apart from the electrochemical merits, this soft matter‐based design also endows the ss‐ZnP electrode with free‐standing and malleable properties which greatly expand its practical application.

Interface coordination regulation of zinc ions for advanced zinc-iodine batteries

Aqueous rechargeable zinc-iodine batteries, as an alternative to lithium-ion batteries (LIBs), deliver the advantages of high theoretical specific capacity, high safety, environmental friendliness, and abundant reserves, making them suitable for large-scale energy storage applications. Nevertheless, unstable Zn anodes would cause a series of symptoms, such as the growth of Zn dendrites and side reactions, which endanger the stability and lifespan of the batteries. Herein, an organic-metal (PAA-Zn) functional film is introduced onto the surface of Zn foil via the coordination of polyacrylic acid and divalent ions to address the above challenges of Zn anodes. The PAA-Zn functional films adjust the uniform distribution of the interfacial electric field, which is advantageous for uniform Zn plating/stripping. Additionally, the abundant oxygen-containing functional groups not only significantly enhance the interfacial hydrophilicity, but also reduce the number of free water molecules reaching the Zn foil surface through the isolation and desolvation effect of functional groups, thus inhibiting corrosion and hydrogen evolution side reactions. As a result, PAA-Zn electrodes exhibited a stable cycling for over 1000 h in symmetrical cells. Most importantly, the Zn-I2 batteries demonstrated a high specific capacity with a retention rate of 89.9 % during 3500 cycles when assembled with PAA-Zn anodes.