Application Of Li-O2 Batteries Research Articles

Ionic Liquid-based Electrolytes for Li Metal/Air Batteries: A Review of Materials and the New 'LABOHR' Flow Cell Concept

The Li-O2 battery has been attracting much attention recently, due to its very high theoretical capacity compared with Li-ion chemistries. Nevertheless, several studies within the last few years revealed that Li-ion derived electrolytes based on alkyl carbonate solvents, which have been commonly used in the last 27 years, are irreversibly consumed at the O2 electrode. Accordingly, more stable electrolytes are required capable to operate with both the Li metal anode and the O2 cathode. Thus, due to their favorable properties such as non volatility, chemical inertia, and favorable behavior toward the Li metal electrode, ionic liquid-based electrolytes have gathered increasing attention from the scientific community for its application in Li-O2 batteries. However, the scale-up of Li-O2 technology to real application requires solving the mass transport limitation, especially for supplying oxygen to the cathode. Hence, the ‘LABOHR’ project proposes the introduction of a flooded cathode configuration and the circulation of the electrolyte, which is then used as an oxygen carrier from an external O2 harvesting device to the cathode for freeing the system from diffusion limitation.

Investigation of Ether-Based Ionic Liquid Electrolytes for Lithium-O2 Batteries

The growing global energy demand of modern society is urging to find large-scale sources, which are more sustainable and environmentally friendly than the oil-based ones. At present, the capacity of the state-of-the-art lithium ion battery is limited and therefore, radically different approaches are required in order to fulfil the very demanding requests of energy storage. Rechargeable Li-O2/air batteries can potentially represent an interesting solution because they theoretically can store more energy than Li-ion batteries. At present numerous aspects of Li-O2 batteries deserve to be carefully investigated before becoming a commercial reality and among them the electrolyte is one of the main challenges.1 Ether based electrolytes have attracted a lot of interest because they combine several beneficial attributes; they are safe, low cost, stable up to 4.5V and they are of low volatility. Tetra(ethylene) glycol dimethyl ether (TEGDME) has been recently employed in Li-O2 batteries and with very good electrochemical performances.2 Hydrophobic ionic liquids (ILs) have been largely employed in case of the conventional Li-ion cells, however a few details on their behaviour in Li-O2batteries are still available.In this work, we investigated the potential use as electrolytes of mixtures of TEGDME and ether functionalized ionic liquids (ILs). We show the results of the characterization of mixtures having different ratio TEGDME-ILs and containing LiCF3SO3 or LiTFSI salt by means of thermal analysis, conductivity and electrochemical stability measurements. In addition, their application in Li-O2 batteries has been assessed, investigating Li/TEGDME-IL/O2 cells by means of cycling voltammetry (CV) and galvanostatic charge-discharge tests. Oxygen reduction and evolution reactions (ORR and OER) have been studied in TEGDME-ILs mixtures to address the mechanism and reversibility of ORR and OER. Our results demonstrate that oxygen reduction and evolution take place in a reversible way and that ether-based electrolytes containing ionic liquids worthwhile of being further investigated for rechargeable Li-O2cells.[1] D. Capsoni, M. Bini, S. Ferrari, E. Quartarone, P. Mustarelli J. Power Sources(2012) 220, 253.[2] H.-G. Jung, J. Hassoun, J.-B. Park, Y.-K. Sun, B. Scrosati Nat. Chem. (2012) 4, 579

Reactivity of Carbon in Lithium–Oxygen Battery Positive Electrodes

Unfortunately, the practical applications of Li-O2 batteries are impeded by poor rechargeability. Here, for the first time we show that superoxide radicals generated at the cathode during discharge react with carbon that contains activated double bonds or aromatics to form epoxy groups and carbonates, which limits the rechargeability of Li-O2 cells. Carbon materials with a low amount of functional groups and defects demonstrate better stability thus keeping the carbon will-o'-the-wisp lit for lithium-air batteries.

Electrochemistry of Hollandite α-MnO2: Li-Ion and Na-Ion Insertion and Li2O Incorporation

MnO2 is attracting considerable interest in the context of rechargeable batteries, supercapacitors, and Li–O2 battery applications. This work investigates the electrochemical properties of hollandi...

Oxygen Reduction Reaction Using MnO2 Nanotubes/Nitrogen-Doped Exfoliated Graphene Hybrid Catalyst for Li-O2 Battery Applications

Nitrogen-doped thermally exfoliated graphene (NExG) synthesized by a simple one-step method combined with α-MnO2 nanotubes (NT) is employed as air cathode materials for lithium oxygen (Li-O2) battery applications. α-MnO2 NT/NExG composite is shown to demonstrate excellent oxygen reduction reaction (ORR) activity in an aprotic non-aqueous electrolyte Li-O2 cell resulting in 2.92 V at the current density of 100 mA g−1, discharge current density of 7.2 A g−1 at 2.2 V, and the maximum power density of 15.8 W g−1 based on carbon mass. This excellent performance of the composite suggests that not only α-MnO2 NT exhibits a remarkable catalytic activity for ORR, but also NExG with a large surface area and high electrical conductivity is capable of catalyzing ORR, demonstrating an outstanding hybrid effect in an aprotic non-aqueous electrolyte Li-O2 cell.