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Organic cations are essential components of locally concentrated ionic liquid electrolytes (LCILEs), but receive little attention. Herein, we demonstrate their significant influence on the electrochemical performance of lithium metal batteries via a comparison study of two LCILEs employing either 1‑butyl‑1-methylpyrrolidinium cation (Pyr14+) or 1-ethyl-3-methylimidazolium cation (Emim+). It is demonstrated that the structure of the organic cation in LCILEs has only a limited effect on the Li+- bis(fluorosulfonyl)imide anion (FSI−) coordination. Nonetheless, the coordination of FSI− with the organic cations is different. The less coordination of FSI− to Emim+ than to Pyr14+ results in the lower viscosity and faster Li+ transport in the Emim+-based electrolyte (EmiBE) than the Pyr14+-based electrolyte (PyrBE). Additionally, the chemical composition of the solid-electrolyte interphase (SEI) formed on lithium metal is affected by the organic cations. A more stable SEI growing in the presence of Emim+ leads to a higher lithium plating/stripping Coulombic efficiency (99.2%). As a result, Li/EmiBE/LiNi0.8Mn0.1Co0.1O2 cells exhibit a capacity of 185 mAh g−1 at 1C discharge (2 mA cm−2) and capacity retention of 96% after 200 cycles. Under the same conditions, PyrBE-based cells show only 34 mAh g−1 capacity with 39.6% retention.

Nowadays, face masks play an essential role in limiting coronavirus diffusion. However, their disposable nature represents a relevant environmental issue. In this work, we propose the utilization of two types of disposed (waste) face masks to prepare hard carbons (biochar) by pyrolytic conversion in mild conditions. Moreover, we evaluated the application of the produced hard carbons as anode materials in Na-ion batteries. Pristine face masks were firstly analyzed through infrared spectroscopy and thermogravimetric analysis. The pyrolysis of both mask types resulted in highly disordered carbons, as revealed by field-emission scanning electron microscopy and Raman spectroscopy, with a very low specific surface area. Anodes prepared with these carbons were tested in laboratory-scale Na-metal cells through electrochemical impedance spectroscopy, cyclic voltammetry and galvanostatic cycling, displaying an acceptable specific capacity along a wide range of current regimes, with a good coulombic efficiency (>98% over at least 750 cycles). As a proof of concept, the anodes were also used to assemble a Na-ion cell in combination with a Na3V2(PO4)2F3 (NVPF) cathode and tested towards galvanostatic cycling, with an initial capacity of almost 120 mAhg−1 (decreasing at about 47 mAhg−1 after 50 cycles). Even though further optimization is required for a real application, the achieved electrochemical performances represent a preliminary confirmation of the possibility of repurposing disposable face masks into higher-value materials for Na-ion batteries.

Herein, we report a comparison of aluminum graphite dual-ion cells (AGDICs) electrochemical characteristics employing the conventional 1-ethyl-3-methylimidazolium chloride:aluminum trichloride (EMIMCl : AlCl3) electrolyte and two popular deep eutectic solvents (DESs), namely urea : AlCl3 and acetamide:AlCl3. The three electrolytes' characteristics have been evaluated in terms of Al-stripping deposition capability and cycling behavior in AGDICs. The results evidence the EMIMCl : AlCl3's Al-stripping deposition and rate capability in AGDICs superior characteristics addressed to the lower viscosity and higher conductivity with respect to the urea : AlCl3 and acetamide:AlCl3. On the other hand, the urea : AlCl3 guarantees a much higher columbic efficiency in AGDICs, thanks to the superior electrochemical window stability.

Rechargeable graphite dual-ion batteries are extremely appealing for grid-level stationary storage of electricity, thanks to the low-cost and high-performance metrics, such as high-power density, energy efficiency, long cycling life, and good energy density. An in-depth understanding of the anion intercalation mechanism in graphite is fundamental for the design of highly efficient systems. In this work, a comparison is presented between pyrolytic (PG) and natural (NG) graphite as positive electrode materials in rechargeable aluminum batteries, employing an ionic liquid electrolyte. The two systems are characterized by operando synchrotron energy-dispersive X-ray diffraction and time-resolved computed tomography simultaneously, establishing a powerful characterization methodology, which can also be applied more in general to carbon-based energy-related materials. A more in-depth insight into the AlCl4−/graphite intercalation mechanism is obtained, evidencing a mixed-staged region in the initial phase and a two-staged region in the second phase. Moreover, strain analysis suggests a correlation between the irreversibility of the PG electrode and the increase of the inhomogenous strain. Finally, the imaging analysis reveals the influence of graphite morphology in the electrode volume expansion upon cycling., In‐depth insight into the AlCl4−/graphite intercalation mechanism is obtained by operando synchrotron energy‐dispersive X‐ray diffraction and time‐resolved computed tomography simultaneously, establishing a powerful characterization methodology, which can also be applied more in general to battery‐related materials. image

Highly concentrated glyme‐based electrolytes are friendly to a series of negative electrodes for potassium‐based batteries, including potassium metal. However, their compatibility with positive electrodes has been rarely explored. In this work, the influence of the molar fraction of potassium bis(trifluoromethanesulfonyl)imide dissolved in glyme on the cycling ability of K/bilayered‐V2O5 batteries has been investigated. At high salt concentration, the interaction between K+ ions with the glyme is strengthened, leading to a limited number of free glyme molecules. Therefore, the anodic decomposition of the electrolyte solvent, as well as the dissolution of the Al current collectors, is effectively suppressed, resulting in the improved cycling ability of the K/bilayered‐V2O5 cells. In these cells, the positive electrode active material exhibits reversible capacities of 93 and 57 mAh g−1 at specific current densities of 50 and 1000 mA g−1, respectively. After 200 charge‐discharge cycles at 500 mA g−1, the cell retains 94 % of the initial capacity. The promising rate performance and capacity retention demonstrate the importance of proper electrolyte engineering for the K/bilayered‐V2O5 batteries, and the good compatibility of highly concentrated glyme‐based electrolytes with positive electrode materials for potassium batteries.

V2O5, one of the earliest intercalation-type cathode materials investigated as a Li+ host, is characterized by an extremely high theoretical capacity (441 mAh g-1). However, the fast capacity fading upon cycling in conventional carbonate-based electrolytes is an unresolved issue. Herein, we show that using a LiTFSI/tetraglyme (1:1 in mole ratio) electrolyte yields a highly enhanced cycling ability of V2O5 (from 20% capacity retention to 80% after 100 cycles at 50 mA g-1 within 1.5-4.0 V vs Li+/Li). The improved performance mostly originates from the V2O5 electrode itself, since refreshing the electrolyte and the lithium electrode of the cycled cells does not help in restoring the V2O5 electrode capacity. Electrochemical impedance spectroscopy (EIS), post-mortem scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS) have been employed to investigate the origin of the improved electrochemical behavior. The results demonstrate that the enhanced cyclability is a consequence of a thinner but more stable cathode-electrolyte interphase (CEI) layer formed in LiTFSI/tetraglyme with respect to the one occurring in 1 M LiPF6 in EC/DMC (1:1 in weight ratio, LP30). These results show that the cyclability of V2O5 can be effectively improved by simple electrolyte engineering. At the same time, the uncovered mechanism further reveals the vital role of the CEI on the cyclability of V2O5, which can be helpful for the performance optimization of vanadium-oxide-based batteries.

Sulfurized polyacrylonitrile (SPAN) is the most promising cathode for next-generation lithium–sulfur (Li–S) batteries due to the much improved stability. However, the molecular structure and reaction mechanism have not yet been fully understood. Herein, we present a new take on the structure and mechanism to interpret the electrochemical behaviors. We find that the thiyl radical is generated after the cleavage of the S–S bond in molecules in the first cycle, and then a conjugative structure can be formed due to electron delocalization of the thiyl radical on the pyridine backbone. The conjugative structure can react with lithium ions through a lithium coupled electron transfer process and form an ion-coordination bond reversibly. This could be the real reason for the superior lithium storage capability, in which the lithium polysulfide may not be formed. This study refreshes current knowledge of SPAN in Li–S batteries. In addition, the structural analysis is applicable to analyze the current organic catho...

Herein we report a novel study on the reaction mechanism of non aqueous aluminum graphite cell chemistry employing 1 ethyl 3 methylimidazolium chloride aluminum trichloride EMIMCl AlCl3 as the electrolyte. This work highlights new insights into the reversibility of the anion intercalation chemistry besides confirming its outstanding cycle life exceeding 2000 cycles, corresponding to more than 5 months of cycling test. The reaction mechanism, involving the intercalation of AlCl4 in graphite, has been fully characterized by means of ex situ X ray diffraction XRD , X ray photoelectron spectroscopy XPS , X ray absorption near edge structure spectroscopy XANES and small angle X ray scattering SAXS , evidencing the accumulation of anionic species into the cathode as the main factor responsible for the slight initial irreversibility of the electrochemical process

This work presents an enhanced hydrometallurgical process for recycling lithium ion batteries. First, end-of-life batteries were processed in a physical pre-treatment plant to obtain a representative electrode material. The resulting leachate was purified forth by iron-precipitation, liquid–liquid extractions, and an innovative Li–Na separation, in order to obtain valuable products. These products include high-grade graphite, cobalt oxide (Co3O4, purity 83%), cobalt oxalate (CoC2O4, purity 96%), nickel oxide (NiO, purity 89%), and lithium carbonate (Li2CO3, purity 99.8%). The recovery rate was quantitative for graphite, between 80% and 85% for cobalt depending on the nature of the recovery method, 90% for nickel, and 72% for lithium. Secondary streams were also valorized to obtain sodium sulfate (Na2SO4, purity 96%), and MnCoFe2O4 magnetic nano-sorbents according to the zero-waste concept. In order to close the loop, recycled Co3O4 and NiO were used as conversion-type anode materials for advanced lithium ion batteries showing promising performances.

Aluminum batteries are considered compelling electrochemical energy storage systems because of the natural abundance of aluminum, the high charge storage capacity of aluminum of 2980 mA h g−1/8046 mA h cm−3, and the sufficiently low redox potential of Al3+/Al. Several electrochemical storage technologies based on aluminum have been proposed so far. This review classifies the types of reported Al-batteries into two main groups: aqueous (Al-ion, and Al-air) and non-aqueous (aluminum graphite dual-ion, Al-organic dual-ion, Al-ion, and Al-sulfur). Specific focus is given to Al electrolyte chemistry based on chloroaluminate melts, deep eutectic solvents, polymers, and “chlorine-free” formulations., Journal of Power Sources, 481, ISSN:0378-7753, ISSN:1873-2755

Herein we studied a rechargeable sodium–oxygen cell operating at room temperature and employing a cathode comprising multi-walled carbon nanotubes coated on a gas diffusion layer. The oxygen reduction reaction (ORR) is investigated and improved by optimizing the cathode configuration. We demonstrated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements that, using a low-volatile tetraethylene glycol dimethyl ether (TEG-DME)-sodium trifluoromethanesulfonate (NaCF3SO3) electrolyte solution, the major discharge product is NaO2. Moreover, we originally demonstrated that controlled amount of superoxide formed at the cathode side by discharge facilitates the oxygen evolution reaction (OER), thus resulting in a charge-discharge polarization as low as 400 mV. The developed system can deliver a capacity of 500 mAh g−1 with an energy efficiency as high as 83% for 60 charge-discharge cycles. The data here reported represent a step-forward in the development of an efficient sodium-air battery.

The massive demand for batteries required by electromobility and stationary storage is pushing the research activity to evaluate electrochemical storage chemistries based on highly abundant elements, as alternatives to state-of-the-art Li-ion ones.[1] The use of more abundant and sustainable elements is expected to reduce the cost and the environmental impact of the energy storage devices. In particular, calcium, the fifth most abundant element in the Earth’s crust also offering non-toxicity, low standard reduction potential (-2.87 vs. SHE), is an appealing candidate for the realization of electrochemical storage devices.[1] However, the conditions to achieve efficient Ca stripping and deposition have not been found yet, due to the formation of passivation products at the Ca/electrolyte interphase, blocking any electrochemical reaction.[2] Although a limited number of electrolytes enabling the stripping deposition have been found, [3–6] they are characterized by a rather limited efficiency, thus making the Ca metal unsuitable for counter and reference electrodes. The resulting lack of a reliable cell configuration limits the possibility to test candidate electrode materials suitable for Ca2+-based electrochemical storage devices, impeding the progress and research on the topic. Here, we propose an alternative cell configuration, employing activated carbon (AC) as counter electrode and quasi reference electrode (QRE), as a reliable system for the electrochemical characterization of electrode materials for Ca-ion batteries.[7] As a prove-of-the-concept, a few electrode materials, i.e., CaV6O16 cathode and graphite anode exploiting co-intercalation mechanism, have been demonstrated electrochemically active in Ca2+-based electrolytes. References: [1] M.E. Arroyo-De Dompablo, A. Ponrouch, P. Johansson, M.R. Palacín, Achievements, Challenges, and Prospects of Calcium Batteries, Chem. Rev. 120 (2020) 6331–6357. [2] D. Aurbach, R. Skaletsky, Y. Gofer, The Electrochemical Behavior of Calcium Electrodes in a Few Organic Electrolytes, J. Electrochem. Soc. 138 (1991) 3536–3545. [3] A. Ponrouch, C. Frontera, F. Bardé, M.R. Palacín, Towards a calcium-based rechargeable battery, Nat. Mater. 15 (2016) 169–172. [4] D. Wang, X. Gao, Y. Chen, L. Jin, C. Kuss, P.G. Bruce, Plating and stripping calcium in an organic electrolyte, Nat. Mater. 17 (2018) 16–20. [5] A. Shyamsunder, L.E. Blanc, A. Assoud, L.F. Nazar, Reversible Calcium Plating and Stripping at Room Temperature Using a Borate Salt, ACS Energy Lett. 4 (2019) 2271–2276. [6] Z. Li, O. Fuhr, M. Fichtner, Z. Zhao-Karger, Towards stable and efficient electrolytes for room-temperature rechargeable calcium batteries, Energy Environ. Sci. 12 (2019) 3496–3501. [7] X. Liu, G.A. Elia, S. Passerini, Evaluation of counter and reference electrodes for the investigation of Ca battery materials, J. Power Sources Adv. 2 (2020) 100008.

An efficient lithium-ion battery was assembled by using an enhanced sulfur-based cathode and a silicon oxide-based anode and proposed as an innovative energy-storage system. The sulfur-carbon composite, which exploits graphene carbon with a 3 D array (3DG-S), was synthesized by a reduction step through a microwave-assisted solvothermal technique and was fully characterized in terms of structure and morphology, thereby revealing suitable features for lithium-cell application. Electrochemical tests of the 3DG-S electrode in a lithium half-cell indicated a capacity ranging from 1200 to 1000 mAh g-1 at currents of C/10 and 1 C, respectively. Remarkably, the Li-alloyed anode, namely, Liy SiOx -C prepared by the sol-gel method and lithiated by surface treatment, showed suitable performance in a lithium half-cell by using an electrolyte designed for lithium-sulfur batteries. The Liy SiOx -C/3DG-S battery was found to exhibit very promising properties with a capacity of approximately 460 mAh gS-1 delivered at an average voltage of approximately 1.5 V over 200 cycles, suggesting that the characterized materials would be suitable candidates for low-cost and high-energy-storage applications.

Cathode configurations reported herein are alternative to the most diffused ones for application in lithium-oxygen batteries, using an ionic liquid-based electrolyte. The electrodes employ high surface area conductive carbon as the reaction host, and polytetrafluoroethylene as the binding agent to enhance the oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) reversibility. Roll-pressed, self-standing electrodes (SSEs) and thinner, spray deposited electrodes (SDEs) are characterized in lithium-oxygen cells using an ionic liquid (IL) based electrolyte formed by mixing lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt and N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium bis(trifluoromethanesulfonyl)imide (DEMETFSI). The electrochemical results reveal reversible reactions for both electrode configurations, but improved electrochemical performance for the self-standing electrodes in lithium-oxygen cells. These electrodes show charge/discharge polarizations at 60 °C limited to 0.4 V, with capacity up to 1 mAh cm-2 and energy efficiency of about 88 %, while the spray deposited electrodes reveal, under the same conditions, a polarization of 0.6 V and energy efficiency of 80 %. The roll pressed electrode combined with the DEMETFSI-LiTFSI electrolyte and a composite Lix Sn-C alloy anode forms a full Li-ion oxygen cell showing extremely limited polarization, and remarkable energy efficiency.

Here we report a low polarization, catalyst-free lithium–oxygen battery using mesoporous carbon electrode. BET analysis, SEM and TEM images evidence that the carbon material has surface area as high as 1500 m 2 g -1 and a uniform distribution of nanometric pores. Furthermore, X-ray diffraction analysis and TEM images of the reaction products show that the favourable effect of the mesoporous carbon is due to the formation of amorphous nano-particles of lithium peroxide during the electrochemical process. The results of this study clearly indicate the important role of the carbon matrix in determining a favourable morphology of the lithium–oxygen reaction product that leads to enhanced cell behaviour.

A cost effective and reliable technology for the fabrication of electrochemical test cell arrays for battery materials investigation, based on batch fabricated glass micro packages was developed and tested. Semi-automatic micro dispensing was investigated as a process for the standardized application of different electrode materials and SiO 2 -based separator. The process shows sufficient reproducibility over the whole range of investigated materials, especially for the cells with interdigital (side-by-side) electrodes. Such setup gives rise to an improved reliability and reproducibility of electrochemical experiments. The economic fabrication of our test chips by batch processing allows for their single-use in electrochemical experiments, herby preventing contamination issues due to repeated use as in conventional laboratory test cells. In addition, the integration of micro pseudo reference electrodes was demonstrated. Thus, the presented test cell array together with the developed electrode/electrolyte deposition technology represents a highly efficient tool for combinatorial and high throughput testing of battery materials on system level (full cell tests). The method will speed up electrochemical materials research significantly.

Herein we report a novel synthetic procedure for the preparation of a SiOx-based nano-composite involving gelification of resorcinol-formaldehyde and tetraethyl orthosilicate. The composite is characterized as anode material in lithium-ion battery. The micrometric, amorphous material has a characteristic nanostructured configuration and shows an electrochemical process involving both the Li-Si alloying and the Li-insertion into the hard carbon matrix. The electrode reveals in lithium half-cell a relatively low impedance and a reversible capacity ranging from 650 mAh g-1 at the lower current to 400 mAh g-1 at high current regimes, with cycle life extending to 200 cycles. The anode is combined with a high voltage, LiNi0.5Mn1.5O4 spinel cathode in a 4.3 V lithium ion battery delivering a capacity of about 115 mAh g-1 and operating at the high rate of 5C. The suitable synthesis pathway, the low cost and the promising electrochemical behavior suggest the nano-composite anode for application in high performance lithium-ion battery.

In this paper we investigate in details the changes occurring in the lithium–oxygen cell during operation in a tetraglyme-base electrolyte, in terms of electrochemical behavior and of carbon electrode morphology. The study evidences a decrease of the cell polarization and impedance during cycling associated with a morphological change of the carbon electrode, as demonstrated by SEM images. We attribute the change of the electrode morphology to the already known carbon oxidation process, here resulting in an increased porosity favoring the reversible electrochemical process. The results here reported shed light on important aspects to be considered in order to better understand the complex behavior of the lithium–oxygen battery. Keywords: Lithium–oxygen battery, Tetraglyme-electrolyte, Impedance spectroscopy, Cathode morphology

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich. This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively. Advanced ionic liquid-based electrolytes are herein characterized for application in high performance lithium-ion batteries. The electrolytes based on either N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (Pyr(14)TFSI), N-butyl-N-methylpyrrolidinium bis(fluoro-sulfonyl) imide (Pyr(14)FSI), N-methoxy-ethyl-N-methylpyrrolidinium bis(trifluoromethane-sulfonyl) imide (Pyr(12O1)TFSI) or N-N-diethyl-N-methyl-N-(2methoxyethyl) ammonium bis(trifluoromethanesulfonyl) imide (DEMETFSI) ionic liquids and lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) salt are fully characterized in terms of ionic conductivity, viscosity, electrochemical properties and lithium-interphase stability. All IL-based electrolytes reveal suitable characteristics for application in batteries. Lithium half-cells, employing a LiFePO4 polyanionic cathode, show remarkable performance. In particular, relevant efficiency and rate-capability are observed for the Py14FSI-LiTFSI electrolyte, which is further characterized for application in a lithium-ion battery composed of the alloying Sn-C nanocomposite anode and LiFePO4 cathode. The IL-based full-cell delivers a maximum reversible capacity of about 160 mA h g(-1) (versus cathode weight) at a working voltage of about 3 V, corresponding to an estimated practical energy of about 160 W h kg(-1). The cell evidences outstanding electrochemical cycle life, i.e., extended over 2000 cycles without signs of decay, and satisfactory rate capability. This performance together with the high safety provided by the IL-electrolyte, olivine-structure cathode and Li-alloying anode, makes this cell chemistry well suited for application in new-generation electric and electronic devices.

In this paper, we report an advanced long-life lithium ion battery, employing a Pyr14 TFSI-LiTFSI non-flammable ionic liquid (IL) electrolyte, a nanostructured tin carbon (Sn-C) nanocomposite anode, and a layered LiNi1/3 Co1/3 Mn1/3 O2 (NMC) cathode. The IL-based electrolyte is characterized in terms of conductivity and viscosity at various temperatures, revealing a Vogel-Tammann-Fulcher (VTF) trend. Lithium half-cells employing the Sn-C anode and NMC cathode in the Pyr14 TFSI-LiTFSI electrolyte are investigated by galvanostatic cycling at various temperatures, demonstrating the full compatibility of the electrolyte with the selected electrode materials. The NMC and Sn-C electrodes are combined into a cathode-limited full cell, which is subjected to prolonged cycling at 40 °C, revealing a very stable capacity of about 140 mAh g(-1) and retention above 99 % over 400 cycles. The electrode/electrolyte interface is further characterized through a combination of electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) investigations upon cell cycling. The remarkable performances reported here definitively indicate that IL-based lithium ion cells are suitable batteries for application in electric vehicles.

In this paper, we propose a new electrolyte formed by dissolving lithium-bis-(trifluoromethanesulfonyl)-imide (LiTFSI) salt in a long chain glyme, i.e. poly(ethylene glycol)500-dimethylether (PEG500DME) mixed with methyl butyl pyrrolidinium-bis-(trifluoromethanesulfonyl)-imide (Pyr14TFSI) ionic liquid. The electrolyte composition ensures both very low volatility and good performance as demonstrated by thermal analysis and electrochemical tests. The selected solution is efficiently employed as the electrolyte both in a lithium–oxygen half-cell, and in a full lithium-ion oxygen battery using a Li–Sn–C nanostructured composite anode, thus suggesting the suitability of the polyethylene glyme mixed with the ionic liquid for application in high-energy storage systems.

Herein we report the characteristics of a lithium-oxygen battery using a solid polymer membrane as the electrolyte separator. The polymer electrolyte, fully characterized in terms of electrochemical properties, shows suitable conductivity at room temperature allowing the reversible cycling of the Li-O2 battery with a specific capacity as high as 25,000 mAh gC−1 reflected in a surface capacity of 12.5 mAh cm−2. The electrochemical formation and dissolution of the lithium peroxide during Li-O2 polymer cell operation is investigated by electrochemical techniques combined with X-ray diffraction study, demonstrating the process reversibility. The excellent cell performances in terms of delivered capacity, in addition to its solid configuration allowing the safe use of lithium metal as high capacity anode, demonstrate the suitability of the polymer lithium-oxygen as high-energy storage system.

International audience; A novel lithium-ion/oxygen battery employing Pyr(14)FSI-LiTESI as the electrolyte and nanostructured LixSn-C as the anode is reported. The remarkable energy content of the oxygen cathode, the replacement of the lithium metal anode by a nanostructured stable lithium-alloying composite, and the concomitant use of nonflammable ionic liquid-based electrolyte result in a new and intrinsically safer energy storage system. The lithium-ion/oxygen battery delivers a stable capacity of 500 mAh g(-1) at a working voltage of 2.4 V with a low charge-discharge polarization. However, further characterization of this new system by electrochemical impedance spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy reveals the progressive decrease of the battery working voltage, because of the crossover of oxygen through the electrolyte and its direct reaction with the LixSn-C anode.

A tin–carbon composite synthesized by high energy mechanical milling (HEMM) technique is characterized here as an anode material for lithium ion battery. The composite morphology and structure are studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD), respectively, and its electrochemical behavior is characterized by cyclic voltammetry (CV) and galvanostatic cycling in lithium cell. The electrode evidences highly nanostructured morphology and enhanced lithium–tin alloying–de-alloying process stability as the mechanical milling time is increased, with capacity ranging from 500 to 400 mAh g−1. Further important characteristic of the tin–carbon nanostructure reported here is the very high rate capability, extending up to 2 A g−1, that finally allows to its application in a high voltage, high rate lithium ion cell using the LiNi0.5Mn1.5O4 spinel cathode. The cell shows a working voltage of 4.3 V and a capacity of 120 mAh g−1 obtained at 1 C rate. The very promising features of the cell, its high energy and power density, and the low cost of the involved materials, suggest that the electrode reported here can be efficiently used as an anode in advanced configuration lithium ion battery.

Due to its high energy density, largely exceeding that of conventional lithium-ion batteries,[1–2] the Li/O2 battery is presently considered as a very promising energy storage system. However, the practical development of this battery is still hindered by several issues, such as: 1) the limited cycle number, affecting its life; 2) the high charge–discharge polarization, resulting in low energy efficiency, and 3) the occurrence of side processes due to moisture and carbon dioxide contamination that preventing its use in open air. The choice of solvent and of electrolyte salt is expected to play a key role in influencing the cell behavior. To further investigate this important aspect, in this work we have examined the response of a Li/O2 cell using a tetraethylene glycol dimethyl ether electrolyte solutions, with four different salts, that is, LiPF6, LiClO4, LiCF3SO3, LiN(SO2CF3)2. This comparative study demonstrates that LiCF3SO3 salt is the best choice for assuring low cell polarization [3]. [1] B. Scrosati, J. Hassoun, Y.-K. Sun, Energy Environ. Sci. 2011, 4, 3287 –3295. [2] G. Girishkumar, B. McCloskey, A. C. Luntz, S. Swanson, W. Wilcke, J. Phys. Chem. Lett. 2010, 1, 2193– 2203. [3] Giuseppe Antonio Elia, Jin-Bum Park, Yang-Kook Sun, Bruno Scrosati, Jusef Hassoun, ChemElectroChem, DOI: 10.1002/celc.201300160.

We demonstrate the feasibility of a lithium ion battery (LIB) using graphene nanosheets (GNS) as the anode in combination with a LiNi(0.5)Mn(1.5)O4 (LNMO) high voltage, spinel-structure cathode. The GNS anode is characterized by a reversible capacity of the order of 600 mA h g(-1) and a working voltage of around 0.9 V, while the 4.8-V cathode has a theoretical capacity of 146.7 mA h g(-1). The full GNS/LiNi(0.5)Mn(1.5)O4 cell has an average working voltage of about 3.75 V and a capacity of the order of 100 mA h g(-1). The findings of this paper suggest that the graphene may be proposed as a suitable anode for application in lithium ion batteries.