High-Voltage Aqueous Zinc Batteries Achieved by Tri-functional Metallic Bipolar Electrodes

Aqueous rechargeable zinc batteries are very attractive for energy storage applications due to their low cost and high safety.However,low operating voltages limit their further development.For the first time,this work proposes a unique approach to increase the voltages of aqueous zinc batteries by using tri-functional metallic bipolar electrode with good electrochemical activity and ultrahigh electronic conductivity,which not only participates in redox reactions,but also functions as an electrical highway for charge transport.Furthermore,bipolar electrode can replace expensive ion selective membrane to separate electrolytes with different pH;thus,redox couples with higher potential in acid condition and Zn=Zn(OH)^(2-)_(4) couple with lower potential in alkaline condition can be employed together,leading to high voltages of aqueous zinc batteries.Herein,two types of metallic bipolar electrodes of Cu and Ag are utilized based on three kinds of aqueous zinc batteries:Zn–MnO_(2),Zn–I_(2),and Zn–Br_(2).The voltage of aqueous Zn–MnO_(2) battery is raised to 1.84 V by employing one Cu bipolar electrode,which shows no capacity attenuation after 3500 cycles.Moreover,the other Ag bipolar electrode can be adopted to successfully construct Zn–I_(2) and Zn–Br_(2) batteries exhibiting much higher voltages of 2.44 and 2.67 V,which also show no obvious capacity degradation for 1000 and 800 cycles,representing decent cycle stability.Since bipolar electrode can be applied in a large family of aqueous batteries,this work offers an elaborate high-voltage concept based on tri-functional metallic bipolar electrode as a model system to open a door to explore high-voltage aqueous batteries.

Performance and mechanistic study on electrocoagulation process for municipal wastewater treatment based on horizontal bipolar electrodes

The design of electrodes is crucial to electrocoagulation process(EC),specifically,with respect to pollutant removal and energy consumption.During EC,the mechanisms for interaction between different electrode arrangement and electrode reactions remain unclear.This work presents an integrated EC process based on horizontal bipolar electrodes(BPEs).In the electrochemical cell,the graphite plates are used as driving cathode while either Fe or A1 plates serves as driving anode and BPEs.The BPEs are placed horizontally between the driving electrodes.For municipal wastewater treatment,the pollutant removal efficiency and energy consumption in different configurations of twodimension electrocoagulation(2D-EC)system with horizontal BPEs were investigated.The removal efficiency of turbidity,total phosphorus and total organic carbon increased significantly with the number of BPEs.Noted that the energy consumption for TP removal decreased by 75.2%with Fe driving anode and 81.5%with A1 driving anode than those of 2D-EC,respectively.In addition,the physical field simulation suggested the distributions of potential and current in electrolyte and that of induced charge density on BPE surface.This work provides a visual theoretical guidance to predict the distribution of reactions on BPEs for enhanced pollutant removal and energy saving based on electrocoagulation process for municipal wastewater treatment.

Disposable paper-based bipolar electrode array for multiplexed electrochemiluminescence detection of pathogenic DNAs

A novel disposable paper-based bipolar electrode （BPE） array is fabricated for multiplexed electrochemiluminescence （ECL） detection of pathogenic DNAs. This proposed BPE array device consists of 15 units, each consisting of six sensing cells and two reporting cells patterned using hydrophobic wax. A hairpin structure DNA assembled on the cathodes of BPEs hybridizes with Pt nanoparticles （NPs） labeled probe DNA in the presence of complementary target DNA. The introduction of Pt NPs catalyzes the reduction of dissolved 02 at cathodes and induces an enhanced ECL signal from Ru（bpy）32＋/tripropylamine （TPrA） at the anodes of BPEs. The dissolved 02 lost in reduction reaction could be promptly replenished due to the relatively large contact area of the paper-based cells with air, which ensures the stability of ECL signal. This obtained paper-based BPE array sensor showed excellent performances for the multiplexed analysis of the syphilis （Treponema pallidum） gene, the immunodeficiency virus gene （HIV） and hepatitis B virus gene （HBV）.

Bipolar electrode architecture enables high-energy aqueous rechargeable sodium ion battery

Aqueous rechargeable sodium ion batteries(ARSIBs),with intrinsic safety,low cost,and greenness,are attracting more and more attentions for large scale energy storage application.However,the low energy density hampers their practical application.Here,a battery architecture designed by bipolar electrode with graphite/amorphous carbon film as current collector shows high energy density and excellent rate-capability.The bipolar electrode architecture is designed to not only improve energy density of practical battery by minimizing inactive ingredient,such as tabs and cases,but also guarantee high rate-capability through a short electron transport distance in the through-plane direction instead of in-plane direction for traditional cell architecture.As a proof of concept,a prototype pouch cell of 8 V based on six Na_(2)MnFe(CN)_(6)||NaTi_(2)(PO_(4))_(3)bipolar electrodes stacking using a“water-in-polymer”gel electrolyte is demonstrated to cycle up to 4,000 times,with a high energy density of 86 Wh·kg^(−1)based on total mass of both cathode and anode.This result opens a new avenue to develop advance high-energy ARSIBs for grid-scale energy storage applications.

Performance of activated carbon coated graphite bipolar electrodes on capacitive deionization method for salinity reduction

This research investigates a capacitive deionization method for salinity reduction in a batch reactor as a new approach for desalination.Reductions of cost and energy compared with conventional desalination methods are the significant advantages of this approach.In this research,experiments were performed with a pair of graphite bipolar electrodes that were coated with a one-gram activated carbon solution.After completing preliminary tests,the impacts of four parameters on electrical conductivity reduction,including(1)the initial concentration of feed solution,(2)the duration of the tests,(3)the applied voltage,and(4)the pH of the solution,were examined.The results show that the maximum efficiency of electrical conductivity reduction in this laboratory-scale reactor is about 55%.Furthermore,the effects of the initial concentration of feed solution are more significant than the other parameters.Thus,using the capacitive deionization method for water desalination with low and moderate salt concentrations(i.e.,brackish water)is proposed as an affordable method.Compared with conventional desalination methods,capacitive deionization is not only more efficient but also potentially more environmentally friendly.

Numerical Study of Pulsed Dielectric Barrier Discharge at Atmospheric Pressure Under the Needle-Plate Electrode Configuration

In this paper, we study the characteristics of atmospheric-pressure pulsed dielectric barrier discharge （DBD） under the needle-plate electrode configuration using a one-dimensional self-consistent fluid model. The results show that, the DBDs driven by positive pulse, negative pulse and bipolar pulse possess different behaviors. Moreover, the two discharges appearing at the rising and the falling phases of per voltage pulse also have different discharge regimes. For the case of the positive pulse, the breakdown field is much lower than that of the negative pulse, and its propagation characteristic is different from the negative pulse DBD. When the DBD is driven by a bipolar pulse voltage, there exists the interaction between the positive and negative pulses, resulting in the decrease of the breakdown field of the negative pulse DBD and causing the change of the discharge behaviors. In addition, the effects of the discharge parameters on the behaviors of pulsed DBD in the needle-plate electrode configuration are also studied.

The treatment of black-odorous water using tower bipolar electro-flocculation including the removal of phosphorus,turbidity,sulfion,and oxygen enrichment

The large amount of municipal wastewater discharged into urban rivers sometimes exceeds the rivers’self-purification capacity leading to black-odorous polluted water.Electro-flocculation has emerged as a powerful remediation technology.Electro-flocculation in a bubble column tower with a bipolar electrode(BPE)was tested in an attempt to overcome the high resistance and weak gas-floatation observed with a monopolar electrode(MPE)in treating such water.The BPE reactor tested had a Ti/Ta2O_(5)-IrO_(2)anode and a graphite cathode with an iron or aluminum bipolar electrode suspended between them.It was tested for its ability to reduce turbidity,phosphate and sulphion and to increase the concentration of dissolved oxygen.The inclusion of the bipolar electrode was found to distinctly improved the system’s conductivity.The system’s electro-flocculation and electrical floatation removed turbidity,phosphate and sulphion completely,and the dissolved oxygen level improved from 0.29 to 6.28 mg/L.An aluminum bipolar electrode performed better than an iron one.Changes in the structure of the microbial community confirmed a significant improvement in water quality.

Design of portable electrochemiluminescence sensing systems for point-of-care-testing applications

Point-of-care testing(POCT)technology is highly desirable for clinical diagnosis,healthcare monitoring,food safety inspection,and environment surveillance,because it enables rapid detection anywhere,anytime,and by anyone.Electrochemiluminescence(ECL)has been widely used in chemo-/bio analysis due to its advantages such as high sensitivity,simplicity,rapidity and easy to control,and is now attracting increasing attention for POCT applications.However,to realize the accurate on-site quantitation,it is still challenging to develop portable devices which can precisely collect,analyze,transmit and display the ECL signals.This review will focus on how to develop a portable ECL device by summarizing recent examples and analyzing their key components part by part.Then the possible solutions to the existing challenges in the development and applications of portable ECL devices are summarized and discussed in detail,followed by offering future perspectives.We attempted to provide an appealing viewpoint to inspire interested researchers to comprehend and explore portable ECL sensing systems for practical applications and even commercialization.

Flexibly regulated electrochemiluminescence of all-inorganic perovskite CsPbBr_(3)quantum dots through electron bridge to across interfaces between polar and non-polar solvents

All-inorganic perovskite quantum dots(QDs)have attracted great interests due to its outstanding properties.But their poor stability in polar solvents seriously hampered wide applications in analytical chemistry.In this work,strong,stable and flexibly regulated the electrochemiluminescence(ECL)emission form CsPbBr(_3)QDs was successfully obtained and applied in the analysis of polar solvents through the unique structure of closed bipolar electrode(BPE).To demonstrate the feasibility,it was successfully used in the detection of tetracycline(Tc)aqueous solution.CsPbBr(_3)QDs was immersed into organic solution in anode microcell of closed BPE while Tc aqueous solution was added into cathode microcell.The two microcells were physically separated and would not interfere with each other.But the bio-recognition event between aptamer and Tc in cathode microcell would induce the ECL signal change in anode microcell through the electrons conducted by BPE as the bridge.The ECL emission can be flexibly regulated by environmental factors of both polar and non-polar solvents and the interface status of the BPE.Compared with traditional methods to overcome the intrinsic instability in polar medium,the reported method does not need any further surface modifications,has no limitations on the targets and can provide wide development space for further deep research,which may open a new direction for the ECL sensing of CsPbBr(_3)QDs.