Highly Conductive Proton Selectivity Membrane Enabled by Hollow Carbon Sieving Nanospheres for Energy Storage Devices

Ion conductive membranes(ICMs)with highly conductive proton selectivity are of significant importance and greatly desired for energy storage devices.However,it is extremely challenging to construct fast proton-selective transport channels in ICMs.Herein,a membrane with highly conductive proton selectivity was fabricated by incorporating porous carbon sieving nanospheres with a hollow structure(HCSNs)in a polymer matrix.Due to the precise ion sieving ability of the microporous carbon shells and the fast proton transport through their accessible internal cavities,this advanced membrane presented a proton conductivity(0.084 S·cm^(-1))superior to those of a commercial Nation 212(N212)membrane(0.033S·cm^(-1))and a pure polymer membrane(0.049 S·cm^(-1)).The corresponding proton selectivity of the membrane(6.68×10^(5) S·min·cm^(-3))was found to be enhanced by about 5.9-fold and 4.3-fold,respectively,compared with those of the N212 membrane(1.13×10^(5) S·min·cm^(-3))and the pure membrane(1.56×10^(5) S·min·cm^(-3)).Low-field nuclear magnetic resonance(LF-NMR)clearly revealed the fast protonselective transport channels enabled by the HCSNs in the polymeric membrane.The proposed membrane exhibited an outstanding energy efficiency(EE)of 84%and long-term stability over 1400 cycles with a0.065%capacity decay per cycle at 120 mA·cm^(-2) in a typical vanadium flow battery(VFB)system.

Modified silicon carbide whisker reinforced polybenzimidazole used for high temperature proton exchange membrane

Polybenzimidazole containing ether bond（OPBI） was reinforced with silicon carbide whisker（m Si C） modified by 3-aminopropyltriethoxysilane（KH550）, and then doped with phosphoric acid（PA） to obtain OPBI/m Si C/PA membranes. These OPBI/m Si C/PA membranes have excellent mechanical strength and oxidative stability and can be used for high temperature proton exchange membrane（HT-PEM）. The tensile strength of OPBI/m Si C/PA membranes ranges from 27.3 to 36.8 MPa, and it increases at first and then decreases with the increase of m Si C content. The high m Si C content and PA doping level contribute to improving the proton conductivity of membranes. The proton conductivity of PBI/m Si C-10/PA membrane is 27.1 m S cm-1 at 170℃ without humidity, with an increase of 55.7% compared with that of OPBI/PA membrane. These excellent properties make OPBI/m Si C/PA membranes promising membrane materials for HT-PEM applications.

Nanocomposite Membranes based on Perfl uorosulfonic Acid/Ceramic for Proton Exchange Membrane Fuel Cells

Perfl uorosulfonic acid/ceramic nanocomposite membranes were investigated as electrolytes for polymer electrolyte membrane fuel cell applications under low relative humidity. Different nanosized ceramics（SiO2, ZrO2, TiO2） with diameters in the range of 2-6 nm were synthesized in situ in Nafion solution through a sol-gel process and the formed nanosized ceramics were well-dispersed in the solution.The nanocomposite membranes were formed through a casting process. The nanocomposite membrane showes enhanced water retention ability and improved proton conductivity compared to those of pure Nafi on membrane. The mechanical strength of the formed nanocomposite membranes is slightly less than that of pure Nafi on membrane. The experimental results demonstrate that the polymer ceramic nanocompsite membranes are potential electrolyte for fuel cells operating at elevated temperature.

Pore-filling Three-dimensionally Ordered Macroporous Polyimide Composite Proton Conducting Membranes

The silica opal templates were prepared from three silica colloids of different diameters of 230 nm, 500 nm and 1.5 mm by a filtration route. The large-scale stable opal template membranes after sintering the deposited SiO2 opal template can be successfully obtained by optimizing the pH value and NaCl concentration in silica colloidal solutions. The three-dimensionally ordered macroporous（3DOM） polyimide membranes without crack were fabricated by reproducing the structure of silica opal template. We prepared the pore-filling composite proton exchange membranes by filling the 3DOM structure with proton conducting organosilane sol. The result indicates that the composite membranes exhibit higher water uptake than pure filling organosilane gel. The proton conductivity increased with the increasing of pore cell in composite membranes.

Electrochemical filtration for drinking water purification:A review on membrane materials,mechanisms and roles

Electrochemical filtration can not only enrich low concentrations of pollutants but also produce reactive oxygen species to interact with toxic pollutants with the assistance of a power supply,making it an effective strategy for drinking water purification.In addition,the application of electrochemical filtration facilitates the reduction of pretreatment procedures and the use of chemicals,which has outstanding potential for maximizing process simplicity and reducing operating costs,enabling the production of safe drinking water in smaller installations.In recent years,the research on electrochemical filtration has gradually increased,but there has been a lack of attention on its application in the removal of low concentrations of pollutants from low conductivity water.In this review,membrane substrates and electrocatalysts used to improve the performance of electrochemical membranes are briefly summarized.Meanwhile,the application prospects of emerging single-atom catalysts in electrochemical filtration are also presented.Thereafter,several electrochemical advanced oxidation processes coupled with membrane filtration are described,and the related working mechanisms and their advantages and shortcomings used in drinking water purification are illustrated.Finally,the roles of electrochemical filtration in drinking water purification are presented,and the main problems and future perspectives of electrochemical filtration in the removal of low concentration pollutants are discussed.

Preparation of electrically enhanced forward osmosis(FO)membrane by two-dimensional MXenes for organic fouling mitigation

In this work,a conductive thin film composite forward osmosis(TFC-FO)membrane was firstly prepared via vacuum filtering MXenes nanolayer on the outer surface of polyethersulfone membrane followed by interfacial polymerization in the other side.Moreover,its feasibility of mitigating organic fouling under electric field was evaluated.Results indicated that the addition of MXenes greatly reduced the electric resistance of membrane from 2.1×10^(12)Ωto 46.8Ω,enhanced the membrane porosity and promoted the membrane performance in terms of the ratio of water flux to reverse salt flux.The modified TFC-FO membrane presented the optimal performance with 0.47 g/m^(2)loading amount of MXenes.Organic fouling experiments using sodium alginate(SA)and bovine serum albumin(BSA)as representative demonstrated that the introduction of MXenes could effectively enhance the anti-fouling ability of TFC-FO membrane under the electric field of 2 V.The interelectron repulsion hindered organic foulants attaching into membrane surface and thus effectively alleviated the membrane fouling.More importantly,the modified TFC-FO membrane showed good stability during the fouling experiment of 10 h.In all,our work proved that introducing MXenes into the porous layer of support is feasible to alleviate organic fouling of FO membrane.

Flexible multiterminal photoelectronic neurotransistors based on self‐assembled rubber semiconductors for spatiotemporal information processing

A significant step toward constructing high‐efficiency neuromorphic systems is the electronic emulation of advanced synaptic functions of the human brain.While previous studies have focused on mimicking the basic functions of synapses using single‐gate transistors,multigate transistors offer an opportunity to simulate more complex and advanced memory‐forming behaviors in biological synapses.In this study,a simple and general method is used to assemble rubber semiconductors into suspended two‐phase composite films that are transferred to the surface of the ion‐conducting membrane to fabricate flexible multiterminal photoelectronic neurotransistors.The suspended ion conductive film is used as the gate dielectrics and supporting substrate.The prepared devices exhibit excellent electrical stability and mechanical flexibility after being bent.Basic photoelectronic synaptic behavior and pulse‐dependent plasticity are emulated.Furthermore,the device realizes the spatiotemporally integrated electrical and optical stimuli to mimic spatiotemporal information processing.This study provides a promising direction for constructing more complex spiking neural networks and more powerful neuromorphic systems with brain‐like dynamic spatiotemporal processing functions.

Cross-stacked super-aligned carbon nanotube/activated carbon composite electrodes for efficient water purification via capacitive deionization enhanced ultrafiltration

The practical application of the capacitive deionization(CDI)enhanced ultrafiltration(CUF)technology is hampered due to low performance of electrodes.The current study demonstrated a novel super-aligned carbon nanotube(SACNT)/activated carbon(AC)composite electrode,which was prepared through coating AC on a cross-stacked SACNT film.The desalination capability and water purification performance of the prepared electrode were systematically investigated at different applied voltages(0.8-1.2 V)with a CDI system and a CUF system,respectively.In the CDI tests,as compared with 5ie control AC electrode,the SACNT/AC electrode achieved an approximately 100%increase in both maximum salt adsorption capacity and average salt adsorption rate under all the applied voltage conditions,demonstrating a superior desalination capability.Meanwhile,a conspicuous increase by an average of-26%in charge efficiency was also achieved at all the voltages.In the CUF tests,as compared with the control run at 0 V,the treatment runs at 0.8,1.0,and 1.2 V achieved a 2.40-fold,2.08-fold,and 2.43-fold reduction in membrane fouling(calculated according to the final transmembrane pressure(TMP)data at the end of every purification stage),respectively.The average TMP increasing rates at 0.8,1.0,and 1.2 V were also roughly two times smaller than that at 0 V,indicating a dramatical reduction of membrane fouling.The SACNT/AC electrode also maintained its superior desalination capability in the CUF process,resulting in an overall improved water purification efficiency.