A novel rechargeable Li/02 battery is reported. It comprises a Li conductive organic polymer electrolyte membrane sandwiched by a thin Li metal foil anode, and a thin carbon composite electrode on which oxygen, the electroactive cathode material, accessed from the environment, is reduced during discharge to generate electric power. It features an all solid state design in which electrode and electrolyte layers are laminated to form a 200 to 300 p.m thick battery cell. The overall cell reaction during discharge appears to be 2Li + °2 Li,0,. It has an open-circuit voltage of about 3 V, and a load voltage that spans between 2 and 2.8 V depending upon the load resistance. The cell can be recharged with good coulombic efficiency using a cobalt phthalocyanine catalyzed carbon electrode. btroduction Electrochemical power sources based on metal/oxygen chemical couples are unique because oxygen, the cathode active material, does not have to be stored in the battery, but rather it can be accessed from the environment. Past efforts to develop such batteries emphasized aqueous systems, utilizing either a KOH/H,0 alkaline electrolyte or a quasi-neutral electrolyte consisting of aqueous solutions of NaCl, NH4C1, (NH4),S04, or KNO,, and conventional design,1 for example as in the alkaline Zn/MnO, battery.Examples of aqueous metal/U, batteries include the Zn/U,, Al/U,, Ca/U,, and Li/0, systems,' although only the Zn/0, battery has become a commercial product; it is used for powering hearing aids.In this paper we report on a novel Li/0, battery that is unlike any metal/oxygen power sources developed to date. It is a nonaqueous thin film battery and consists of a thin L metal foil anode, a thin solid polymer electrolyte membrane that conducts Li ions, and a thin carbon composite electrode sheet made up of high surface area carbon on which oxygen, the electroactive cathode material, accessed from the environment, is reduced during battery discharge to generate electric power. The organic polymer electrolyte membrane serves both as the separator that electronically insulates the cathode from the anode and the medium through which Li ions are transported from the Li anode to the oxygen cathode during discharge.' The present Li/oxygen cell appears to be rechargeable due to the use of nonaqueous electrolyte. The design of this novel battery is a radical departure from that of traditional polymer electrolyte-based Li batteries in which the cathode comprises Li intercalating solid-state materials such as TIS,, V0,,, LiMn,04, and LiCoO,. 2 ExperimentdThe general experimental procedures, materials treatment, and cell construction were as follows. All experiments were carried out either in a Vacuum Atmospheres Corporation argon-filled dry box or in a dry room maintained with less than 1% humidity. Chevron carbon containing cobalt catalyst was prepared as follows: 0.5 g of cobalt phthalocyanine was dissolved in about 30 ml of concentrated [30 weight percent (w/o)] sulfuric acid. The resulting viscous liquid was poured onto 9.5 g of ...

Polymer electrolyte membranes comprising poly(vinylidene fluoride)−hexafluoropropene (PVdF−HFP) copolymer plasticized with a solution of LiSO3CF3, LiN(SO2CF3)2, or LiPF6 in oligomeric poly(ethylene glycol) dimethyl ethers (PEGDME, M w = 250, 400, and 500) were prepared by hot-melt-rolling or solvent-casting techniques. Since the electrolytes containing PEGDME400 and PEGDME500 are “dry” with essentially no volatile components up to 150 °C, we have dubbed them PEO-like. Their thermal stability, mechanical strength, conductivity, electrochemical stability window, and Li/electrolyte interface stability were characterized. Plasticizing PVdF−HFP with the PEGDME/LiX solutions disordered the polymer structure leading to polymer electrolytes having lower crystallinity than the polymer host itself. The mechanical strength of the electrolyte membranes varied depending on the PVdF content. Tensile strength (stress) as high as 420 psi at an elongation-at-break value (strain) of 75% was observed. The conductivities of the electrolytes correlated with the molecular weights of PEGDME as well as the concentration of the Li salt, and most of the electrolytes prepared showed room-temperature conductivities of greater than 10-4 S/cm. The high room-temperature conductivity of these electrolytes compared to PEO-based electrolytes is attributed to the high mobility of the ionic charge carriers. The Li/electrolyte interface stability under open-circuit conditions was found to be good as assessed from the small change in the interfacial impedance for the measured case of the PVdF−PEGDME500−LiN(SO2CF3)2 electrolyte. This electrolyte also showed oxidation stability up to 4.5V versus Li+/Li on Al, Ni, and stainless steel (SS) and reduction stability down to 0.0V versus Li+/Li on both Ni and SS. The applicability of these electrolytes in batteries was demonstrated by the fabrication and testing of Li/oxygen and Li/LiMn2O4 cells.

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Ammonia, a key precursor for fertilizer production, convenient hydrogen carrier, and emerging clean fuel, plays a pivotal role in sustaining life on Earth. Currently, the main route for NH synthesis is by the heterogeneous catalytic Haber-Bosch process (N +3 H →2 NH ), which proceeds under extreme conditions of temperature and pressure with a very large carbon footprint. Herein we report that a pristine nitrogen-doped nanoporous graphitic carbon membrane (NCM) can electrochemically convert N into NH in an acidic aqueous solution under ambient conditions. The Faradaic efficiency and rate of production of NH on the NCM electrode reach 5.2 % and 0.08 g m h , respectively. Functionalization of the NCM with Au nanoparticles dramatically enhances these performance metrics to 22 % and 0.36 g m h , respectively. As this system offers the potential to be scaled to industrial levels it is highly likely that it might displace the century-old Haber-Bosch process.

Herein we firstly introduce a straightforward, scalable and technologically relevant strategy to manufacture charged porous polymer membranes (CPMs) in a controllable manner. The pore sizes and porous architectures of CPMs are well-controlled by rational choice of anions in poly(ionic liquid)s (PILs). Continuously, heteroatom-doped hierarchically porous carbon membrane (HCMs) can be readily fabricated via morphology-maintaining carbonization of asprepared CPMs. These HCMs being as photothermal membranes exhibited excellent performance for solar seawater desalination, representing a promising strategy to construct advanced functional nanomaterials for portable water production technologies.Charged porous polymer membranes (CPMs) have been attracting widespread attention in both academia and industry because they can serve as a multifunctional platform beyond merely filtration membranes. 1 Particularly, the synergy of pore confinement, charges and flexible design in surface chemistry endows them versatile for device fabrication, 2 separation, 3 controlled release, 4 catalyst supports, 5 bio-interfacing, 6 sensors, 7 etc. However, their unique charge nature of CPMs inherently challenges the state-of-the-art membrane fabrication techniques, 8 retarding their development and utilization. There are generally three strategies to fabricate CPMs: (i) selfassembly and dewetting of block copolymers or their blends; 9 (ii) electrostatic layer-by-layer assembly under carefully designed conditions on a laboratory scale 10 ; (iii) electrostatic complexation, especially between a hydrophobic polycation and a hydrophilic polyanion. 11 While the former two suffer from considerable time-and labor-demand and difficulties in obtaining freestanding, interconnected porous membranes, the latter is free of these problems but much