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A full-field high-resolution x-ray nano-tomography technique, transmission x-ray microscopy (TXM), was used to reveal the 3D morphology of the lithium ion battery composite positive electrode: LiCoO2 (LCO)–Li(Ni1/3Mn1/3Co1/3)O2 (NMC). The TXM method allowed the unambiguous chemical identification of oxide particles by tuning the x-ray energy relative to the transition-metal absorption edges. The NMC particles have a much rougher surface compared to the LCO particles. Cracks due to processing exist in both LCO and NMC particles but the NMC particles exhibit more severe cracking and also tend to have internal pores in addition to radial cracks. Further, the carbon-based phases including the binder and the conductive carbon were identified using Zernike phase contrast imaging. Keywords: 3D structural analysis, Li-ion battery, X-ray nano-tomography

The ternary compound cobalt antimony sulfide (CoSbS; mineral name: paracostibite) and CoSbS/C nanocomposite were prepared using simple solid-state synthetic routes, and their potential as electrode materials for rechargeable Li batteries was investigated. The reaction mechanism between CoSbS and Li was examined using ex situ X-ray diffraction and extended X-ray absorption fine structure analyses. The fabricated CoSbS/C nanocomposite electrode exhibited good electrochemical performances such as high capacity, long cycling behavior, and high rate capability. Keywords: Lithium batteries, Electrode materials, Nanocomposite, Cobalt antimony sulfide

How the structural changes of each active material in mixed cathode systems take place at different charge–discharge rates is quite important in the application of the system in which the mixed cathode materials with different rate capabilities are formed into one composite electrode. Here we report the results of the real time structural change studies of mixed LiMn2O4–LiNi1/3Co1/3Mn1/3O2 composite cathode in a Li-ion cell by using in situ synchrotron-based time resolved x-ray diffraction (TR-XRD) technique. The layer structured component in the mixed composite cathode system shows less utilization at fast discharge rate (high power mode) whereas the spinel structured component is fully utilized. This clearly demonstrates that the reduced capacity at fast discharge rate for this system is caused by the less utilization of the layer structured component. The real time monitoring of the structural behavior at various discharge rates is a great tool to design the best ratios of active materials with different rate capabilities in the mixed cathode systems for different applications. Keywords: Lithium battery, Time-resolved XRD, Composite cathode, LiMn2O4, LiNi1/3Co1/3Mn1/3O2

A new type of material, Ni1-xCoxO, was developed for solid oxide fuel cell (SOFC) cathode/interconnect contact applications. The phase structure, coefficient of thermal expansion, sintering behavior, electrical properties, and mechanical bonding strength of these materials were evaluated against the requirements of the SOFC cathode/interconnect contact. A dense cathode/interconnect contact layer was developed through reaction sintering from Ni and Co metal powders. An area specific resistance (ASR) as low as 5.5 mΩ cm2 was observed after 1200 h exposure in air at 800 °C for the LSM/Ni0.33Co0.67O/AISI441 assembly. Average mechanical strengths of 6.8 and 5.0 MPa were obtained for the cathode/contact/cathode and interconnect/contact/interconnect structures, respectively. The significantly low ASR was probably due to the dense structure and therefore improved electrical conductivity of the Ni0.33Co0.67O contact and the good bonding of the interfaces between the contact and the cathode, and between the contact and the interconnect. Keywords: Solid oxide fuel cell, Interconnect/cathode contact, Reaction sintering, Area specific resistance, Mechanical strength

The p-type CaFe2O4 nanofilms with a thickness of about 100 nm on F doped tin-oxide-coated (FTO) glass sheets were fabricated by a pulsed laser deposition (PLD) method at a relatively low temperature. Furthermore, their photoelectrochemical properties for splitting water into hydrogen have also been studied in detail. It has been found that these CaFe2O4 thin films exhibit high photoelectrochemical performances (−117 μA/cm2 at −0.3 vs. SCE) for the hydrogen generation reaction even without applying any external voltage. Keywords: Photoelectrode, CaFe2O4, p-type, Thin film, Hydrogen generation

The role of protection layer coated on cathode is described in terms of chemical and electrochemical stabilities. LiCoO2 electrode is protected by LiNi0.5Mn1.5O4 overlayer through a Gravure coating. Electrochemically inactive LiNi0.5Mn1.5O4 overlayer plays an important role in stabilizing LiCoO2 surface to have less cobalt metal dissolution during high voltage and temperature electrochemical reactions, and the possible stabilization mechanism is suggested with some evidences from physicochemical analyses. Keywords: LiCoO2, LiNi0.5Mn1.5O4, Protection layer, Gravure coating

Using a micro-patterned Si plate, a Li secondary cell was assembled and tested for its electrochemical properties. A micro-patterned Si plate was made by photolithography. This was followed by Pt coating and Li deposition. With a non-lithiated LiV3O8 cathode, a Li-deposited micro-patterned Si anode was assembled as a secondary cell. The cell exhibited an initial charge/discharge capacity of about 220 mAh g−1 at a current density of 0.1 C-rate and it continued for more than 100 cycles without failure. The morphologies of Li deposition/dissolution in the anode were observed via scanning electron microscopy (SEM). Dendrite behavior of the Li metal was not observed on the anode during the cyclic process. Keywords: Micro-patterned Si anode, Li metal, Dendrite, Secondary cell, LiV3O8

A lithium-rich nickel-manganese oxide compound Li x (Ni 0.25 Mn 0.75 )O y ( x > 1) was synthesized from layered Na 0.9 Li 0.3 Ni 0.25 Mn 0.75 O δ precursor using a lithium ion-exchange reaction. The electrochemical behavior of the material as a cathode for lithium batteries, and a preliminary discussion of its structure are reported. The product Li 1.32 Na 0.02 Ni 0.25 Mn 0.75 O y (IE-LNMO) shows broad X-ray diffraction peaks, but possesses a high intensity sharp (003) layering peak and multiple peaks with intensity in the 20–23° 2 θ region which suggest Ni–Mn ordering in the transition metal layer (TM). Li/IE-LNMO cells demonstrate very stable reversible capacities of 220 mAh/g @ 15 mA/g and possess extremely high power of 150 mAh/g @ 1500 mA/g (15C). The Li/IE-LNMO cell d Q /d V plot exhibits three reversible electrochemical processes due to Ni/Mn redox behavior in a layered component, and Mn redox exchange in a spinel component. No alteration in the d Q /d V curves and no detectable change in the voltage profiles over 40 cycles were observed, thus indicating a stable structure for lithium insertion/extraction. This new material is attractive for demanding Li-ion battery applications.

Nanorods of MnO2, Mn3O4, Mn2O3 and MnO are synthesized by hydrothermal reactions and subsequent annealing. It is shown that though different oxides experience distinct phase transition processes in the initial discharge, metallic Mn and Li2O are the end products of discharge, while MnO is the end product of recharge for all these oxides between 0.0 and 3.0 V vs. Li+/Li. Of these 4 manganese oxides, MnO is believed the most promising anode material for lithium ion batteries while MnO2 is the most promising cathode material for secondary lithium batteries. Keywords: Structural evolution, Manganese oxides, Electrode material, Lithium batteries, Metallic Mn

5–10 μm long, typically 200–300 nm wide, and several nanometers thick LixV2O5 (×∼0.8) nanobelts with the δ-type crystal structure were synthesized by a hydrothermal treatment of Li+-exchanged V2O5 gel. When dried at 200 °C under vacuum prior to electrochemical testing, the as-prepared nanobelts underwent the well-known δ→ε→γ-phase transition giving a mixture of ε and γ phases as a nanocomposite electrode material. Such a simple preparation procedure guarantees a yield of material with drastically enhanced initial discharge specific capacity of 490 mAh/g and great cyclability. The enhanced electrochemical performance is attributed to the complex of experimental procedures including post-synthesis treatment of the single-crystalline LixV2O5 nanobelts. Keywords: Vanadium oxide, Hydrothermal, Nanomaterials, Lithium batteries

TiO2–SrTiO3 heterostructure nanotube arrays have been utilized as a novel oxide substrate for CdS quantum dot sensitized solar cells (QDSCs). SrTiO3 on TiO2 surface passivates surface states of TiO2 and builds cascade-structured band alignment, which significantly reduces charge recombination at electrode surface. CdS/TiO2–SrTiO3 electrode exhibits a superior photoelectrochemical performance than CdS/TiO2 electrode with ∼70% increase in external quantum efficiency. This study suggests that the suppression of charge recombination at electrode surface is critical to efficient solar energy conversion. Keywords: TiO2–SrTiO3 nanotube arrays, Quantum dot sensitized solar cells, Electron injection, Charge recombination, Solar energy conversion

Hydrothermally prepared 100 nm-sized LiCoO2 with a plate morphology packed in a crucible resulted in 40 μm-sized particles that consisted of aggregated

The impact of the formation of an electrolyte based decomposition layer on the distribution of the active grain kinetics has been investigated operando within a cycling electrode for lithium battery. It is demonstrated, from fitting procedure of the electrochemical responses and from operando XRD experiments, that as the passive film forms, slow reacting grains appear within the working electrode and operate simultaneously with faster grains. Slow grains are macroscopically distributed, presumably at the electrolyte side of the electrode. Discrimination of the electrochemical response pertaining to each type of grains allows rationalizing their contribution to the capacity fading dynamics. Keywords: Slow and fast grains, Electrochemical peak fitting, Operando XRD, Capacity fading, Electrolyte decomposition, Li battery

We present an analysis of the thermal reduction of delithiated LiMnPO[subscript 4] and LiFePO[subscript 4] based on the quarternary phase diagrams as calculated from first principles. Our results confirm the recent experimental findings that MnPO[subscript 4] decomposes at a much lower temperature than FePO[subscript 4], thereby potentially posing larger safety issues for LiMnPO[subscript 4] cathodes. We find that while substantial oxygen is released as MnPO[subscript 4] reduces to Mn[subscript 2]P[subscript 2]O[subscript 7], the mixed valence phases that form in the decomposition process of FePO[subscript 4] limit the amount of oxygen evolved., United States. Dept. of Energy (Contract No. DE-FG02-05ER46253), United States. Dept. of Energy (Contract No. DE-FG02-97ER25308), National Science Foundation (U.S.) (Grant No. DMR-0606276), Umicore Group, Robert Bosch GmbH

The stability of potassium ferrate(VI) (K2FeO4) electrodes was dramatically improved by using 2,3-Naphthalocyanine (C48H26N8) as coating. The electrode material with the coating was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). K2FeO4 electrodes coated with 2,3-Naphthalocyanine provided a superior capacity and stability to uncoated K2FeO4 electrodes. Cathodic charge capacity of K2FeO4 coated with 2,3-Naphthalocyanine is 42% higher than that of K2FeO4 uncoated when discharged at rate of 0.25 C to a cutoff of 0.8 V after storing in the 10 mol/L KOH solution for 3 h. Keywords: Potassium ferrate(VI) cathode, Stabilized, 2,3-Naphthalocyanine, Coating, Alkaline super iron battery

The performance of Li7.9MnN3.2O1.6 and Li7MnN4 as electrode materials in lithium batteries was analyzed. At 1C rate, capacities of 180 and 230 mAh/g, respectively, were obtained after 50 cycles. If the first charge is done at 0.1C, outstanding capacities of 120–135 mAh/g are observed after 100 cycles at 5C. More lithium can be removed during the charge at 0.1C, leading to a large amount of lithium vacancies that enhance mobility and rate capability. It is proposed that incomplete filling of the vacancies occurs upon cycling, so that the mobility remains high. This performance compares well to that of Li4Ti5O12. Keywords: Lithium batteries, Lithium manganese nitride and oxynitride, Rate capability, Negative electrodes

A power density of over 1.4 W cm−2 at 0.7 V was achieved at 750 °C for an anode-supported YSZ thin electrolyte fuel cell with a dense Sm0.2Ce0.8O1.9 (SDC) interlayer fabricated by pulsed laser deposition, while the cell with a conventional porous SDC interlayer exhibited only 0.8 W cm−2 at this voltage. The dense SDC interlayer significantly reduced the ohmic resistance of the fuel cell. For example, at 750 °C, the ohmic resistance of the fuel cell with a dense SDC interlayer was 0.08 Ω cm2; while that of the cell with a porous SDC interlayer fabricated by conventional screen-printing was 0.16 Ω cm2. The pronounced reduction in ohmic resistance might be due to the fully dense structure and thus improved electrical conductivity of the SDC interlayer, increased contact area at the interface between the dense SDC interlayer and the YSZ electrolyte, and suppressed Zr migration into the SDC interlayer. Keywords: IT-SOFC, Anode-supported, YSZ electrolyte, Dense SDC interlayer, Pulsed laser deposition, Ohmic resistance

Lithium nickel manganese oxide (LiNi1/2Mn1/2O2) was coated on spinel lithium manganese oxide (LiMn2O4) by a sol–gel process in an attempt to improve the high temperature cycling performance. The ratio of the coating sol to LiMn2O4 was adjusted to determine the relationship between the coating thickness and electrochemical performance. The crystal structure and morphology of the samples were examined by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The charge and discharge characteristics, including cyclability and electrochemical properties of the bare and the coated LiMn2O4, were measured and compared. The results showed that a LiNi1/2Mn1/2O2 coating on LiMn2O4 improves the rate capability at room temperature, and the cyclability at high temperatures. Keywords: Spinel, Cyclability at high temperature, Rate performance, Lithium nickel manganese oxide, Sol–gel coating

Well-dispersed (Cd(0.8)Zn(0.2))S single crystal nanorods were synthesized by a facile solvothermal route. The (Cd(0.8)Zn(0.2))S nanorods exhibit wide visible light absorption up to 550 nm. The photocurrent of the (Cd(0.8)Zn(0.2))S photoanode is three times higher that of pure CdS, and 1710 and 3020 mu mol h(-1) g(-1) of H(2) was photocatalytically evolved from aqueous solutions containing SO(3)(2-) and S(2-) sacrificial reagents by the (Cd(0.8)Zn(0.2))S nanorods without and with 3 wt% Pt co-catalyst under a simulated solar light irradiation, respectively. Furthermore, the (Cd(0.8)Zn(0.2))S nanorods show a high photocatalytic stability for H(2) evolution under a long-term light irradiation. (C) 2009 Elsevier B.V. All rights reserved.

Sulfone-based electrolytes have been investigated as electrolytes for lithium-ion cells using high-voltage positive electrodes, such as LiMn{sub 2}O{sub 4} and LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} spinels, and Li{sub 4}Ti{sub 5}O{sub 12} spinel as negative electrode. In the presence of imide salt (LiTFSI) and ethyl methyl sulfone or tetramethyl sulfone (TMS) electrolytes, the Li{sub 4}Ti{sub 5}O{sub 12}/LiMn{sub 2}O{sub 4} cell exhibited a specific capacity of 80 mAh g{sup -1} with an excellent capacity retention after 100 cycles. In a cell with high-voltage LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} positive electrode and 1 M LiPF{sub 6} in TMS as electrolyte, the capacity reached 110 mAh g{sup -1} at the C/12 rate. When TMS was blended with ethyl methyl carbonate, the Li{sub 4}Ti{sub 5}O{sub 12}/LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} cell delivered an initial capacity of 80 mAh g{sup -1} and cycled fairly well for 1000 cycles under 2C rate. The exceptional electrochemical stability of the sulfone electrolytes and their compatibility with the Li{sub 4}Ti{sub 5}O{sub 12} safer and stable anode were the main reason behind the outstanding electrochemical performance observed with high-potential spinel cathode materials. These electrolytes could be promising alternative electrolytes for high-energy density battery applications such as plug-in hybrid and electric vehicles that require amore » long cycle life.« less

The rate capability of high capacity xLi{sub 2}MnO{sub 3} {center_dot} (1 - x)LiMO{sub 2} (M = Mn, Ni, Co) electrodes for lithium-ion batteries has been significantly enhanced by stabilizing the electrode surface by reaction with a Li-Ni-PO{sub 4} solution, followed by a heat-treatment step. Reversible capacities of 250 mAh/g at a C/11 rate, 225 mAh/g at C/2 and 200 mAh/g at C/1 have been obtained from 0.5Li{sub 2}MnO{sub 3} {center_dot} 0.5LiNi{sub 0.44}Co{sub 0.25}Mn{sub 0.31}O{sub 2} electrodes between 4.6 and 2.0 V. The data bode well for their implementation in batteries that meet the 40-mile range requirement for plug-in hybrid vehicles.

One step electrodeposition with an alternating double-potentiostatic(DPSED) program was used to prepare CuInSe2 thin films in nearly neutral aqueous electrolytes with sodium citrate complex. Linear sweep voltammetry(LSV) was measured to probe voltammetric properties of electrolytes with respect to Cu, In and Se individual precursor and their mixed solutions. Compositional and structural characteristics of the as-deposited and annealed films at 400 °C in Ar atmosphere for 0.5 h were analyzed by XRD and XPS. The results showed that reduction of Cu2+ to Cu+ at one potential point of −800 mV and subsequently formation of CuIn alloy as well as metal In and amorphous Se at the other potential point of −1400 mV were responsible for synthesis of CISe chalcopyrite. Composition self-regulation made DPSED films have three elements co-deposition and more uniform element distribution, which promoted chalcopyrite CISe formation. Keywords: CuInSe2, Electrodeposition, Double-potentiostatic, Neutral electrolyte, Thin film

The influence of Sn substitution in LiMn2O4 thin films as a cathode has been studied via solution deposition to improve the electrochemical performance of thin film lithium batteries. LiSn0.025Mn1.95O4 thin films showed the most promising performance, i.e. a high capacity retention of 77% at 10 C after the 500th cycle, due to the increased average Mn valence state. The thin films of LiSnx/2Mn2−xO4 (x ⩾ 0.10) showed significant precipitation of SnO2 and SnO after the cycling evaluation. Keywords: Spinel, Cathode, Sn substitution, Solution deposition, Cycleability

Novel core–shell SDC (Ce0.8Sm0.2O1.9)/amorphous Na2CO3 nanocomposite was prepared for the first time. The core–shell nanocomposite particles are smaller than 100 nm with amorphous Na2CO3 shell of 4–6 nm in thickness. The nanocomposite electrolyte shows superionic conductivity above 300 °C, where the conductivity reaches over 0.1 S cm−1. Such high conductive nanocomposite has been applied in low-temperature solid oxide fuel cells (LTSOFCs) with an excellent performance of 0.8 W cm−2 at 550 °C. A new potential approach of designing and developing superionic conductors for LTSOFCs was presented to develop interface as ‘superionic highway’ in two-phase materials based on coated SDC. Keywords: Ce0.8Sm0.2O1.9 (SDC), Core–shell structure, Amorphous, Composite electrolyte, Solid oxide fuel cells (SOFCs)

La and Sc co-doped SrTiO3 was synthesized via solid state reaction. The oxygen ion migration energy was investigated by first-principles calculations in SrBO3 systems (B = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Ga, Ge, As, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Cd, In, Sn and Sb) with perovskite structure. Structure with Sc showed the lowest oxygen migration energy, and thus Sc was selected as B-site dopant with the primary aim to improve the ionic conductivity of SrTiO3-based anode materials. With increasing Sc-doping amount, the electrical conductivity of La0.3Sr0.7ScxTi1−xO3−δ decreased in 25–1000 °C, while the ionic conductivity increased significantly between 500 and 1000 °C. The ionic conductivity for La0.3Sr0.7Sc0.10Ti0.90O3−δ was 1 × 10−2 S cm−1 and increased about 230% compared with La0.3Sr0.7TiO3−δ at 800 °C and under oxygen partial pressure of 10−19 atm. Sc-doping increased the oxygen vacancy concentration and decreased the oxygen migration energy, thus facilitating the conduction process of oxygen ions in La and Sc co-doped SrTiO3. The possible charge compensation mechanism of Sc-doped La0.3Sr0.7TiO3−δ can be described as La0.3Sr0.7Scx3+Ti0.7-2δ-x14+Ti0.3+2δ-x23+O3-(δ+x1/2) (x = x1 + x2). Keywords: Solid oxide fuel cells, Anode, Oxygen ion migration energy, SrTiO3, Ionic conductivity, Charge compensation mechanism

Nanocrystalline ZnMn2O4 is prepared by a polymer-pyrolysis route and used as a novel anode for lithium ion batteries. XRD and HRTEM studies reveal that the products are highly phase-pure and 30–60 nm in size. Galvanostatic cycling of ZnMn2O4 electrode at 100 mA g−1 (about 0.52 mA cm−2) between 0.01 and 3.0 V up to 50 cycles exhibits almost stable cycling performance between 10 and 50 cycles with only an average capacity fade of 0.20% per cycle and the electrode still maintains a capacity of 569 mAh g−1 after 50 cycles. Keywords: ZnMn2O4 nanocrystals, Anode, Lithium ion batteries, Polymer-pyrolysis

The effect of Li doping in spinel Li4+xTi5−xO12 (0 ⩽ x ⩽ 0.2) materials on the structural and electrochemical properties were investigated. The ratio of the capacity in the voltage plateau (1.5 V) to the overall discharge capacity for Li4.1Ti4.9O12 (x = 0.1) and Li4.2Ti4.8O12 (x = 0.2) were higher than that of Li4Ti5O12 especially at high current rates due to their enhanced lithium-ion and electronic conductivity by the substitution of Ti atoms by Li atoms. With the increasing of Li doping amount, lithium-ion and electronic conductivity of Li4+xTi5−xO12 increased, however its cycling stability was depressed when the Li doping was of x = 0.2. The Li doping of x = 0.1, the appropriate Li doping amount, showed improved rate capability and better high rate performance comparing to undoped Li4+xTi5−xO12 (x = 0). Keywords: Lithium-ion batteries, Spinel, Li4Ti5O4, Lithium-rich framework, Electronic conductivity, Lithium-ion conductivity

Cycling stability, reversible capacity and rate performance of Li4Ti5O12 discharged to 0.01 V were investigated. A couple of obvious and repeatable peaks under 0.6 V observed by CV indicated that Li4Ti5O12 possessed reversible capacity below 0.6 V. When discharge voltage of Li4Ti5O12 extended from 0.6 to 0.01 V, its cycling stability was not affected and its reversible capacity and high rate performance were improved. Although the capacity obtained from 2.0 to 0.6 V gradually decreased with increasing the applied current density, the capacity obtained from 0.6 to 0.01 V showed little loss. AB was both electronic conducting additive and lithium-ion conducting additive for Li4Ti5O12 under 0.6 V. Keywords: Li4Ti5O12, Reversible capacity, Cycling stability, Rate performance, Discharge voltage, AB

NiO, Li0.68Ni1.32O2 and Li0.68Ni1.32O2/Ag composite as anodes for Li-ion batteries are reported. Li0.68Ni1.32O2 decomposed to Ni and Li2O when discharged to 0.02 V, according to XRD analysis, which was similar to NiO. Increased initial coulombic efficiency was obtained for the Li0.68Ni1.32O2 electrode (73%), higher than that of NiO (64.9%), but its cycling performance became worse because poorer conductive Li2O formed when the first discharge process was finished. However, the Li0.68Ni1.32O2/Ag electrode exhibited better cycling performance than NiO and Li0.68Ni1.32O2, because the Ag nanoparticles in the composite improved the conductivity of the electrode. The initial coulombic efficiency for Li0.68Ni1.32O2/Ag is still as high as 72%, nearly the same as that of Li0.68Ni1.32O2. Keywords: NiO, Li0.68Ni1.32O2/Ag nanocomposite, Lithium ion battery

A novel concept of ceramic or solid oxide fuel cell (SOFC) based on non-ceria-salt-composites electrolyte has been investigated. The fuel cell using LiAlO2-carbonate (LiNaCO3) as electrolyte exhibits excellent performances, when we used hydrogen and air as fuel and oxidant respectively, instead of molten carbonate fuel cells (MCFCs) environment. The maximum output power density can reach 466 mW/cm2 at 650 °C and the discharging current keeps constant. The ion transport mechanics of the ceramic fuel cell were discussed. In the H2/air atmosphere, the new fuel cell function should be performed only by proton or oxygen ion conduction, which differs essentially from the MCFC function, in which the CO32- conduction dominates process. Keywords: LiAlO2, Carbonate, Non-ceria-based composite electrolytes, Fuel cells

We report the first example of an intercalation compound based on the nitrogen framework in which lithium can be intercalated and deintercalated. A comparison of the structural and electrochemical properties of the ternary lithium cobalt, nickel and copper nitrides is performed. Vacancy layered structures of ternary lithium nitridocobaltates Li3−2xCoxN and nitridonickelates Li3−2xNixN with 0.10 ⩽ x ⩽ 0.44 and 0.20 ⩽ x ⩽ 0.60, respectively, are proved to reversibly intercalate Li ions in the 1 V–0.02 V potential range. These host lattices can accommodate up to 0.35 Li ion par mole of nitride. Results herein obtained support Li insertion in vacancies located in Li2N− layers while interlayer divalent cobalt and nickel cations are reduced to monovalent species. No structural strain is induced by the insertion–extraction electrochemical reaction which explains the high stability of the capacity in both cases. For the Li1.86Ni0.57N compound, a stable faradaic yield of 0.30 F/mol, i.e. 130 mAh/g, is maintained at least for 100 cycles. Conversely, the ternary copper nitrides corresponding to the chemical composition Li3−xCuxN with 0.10 ⩽ x ⩽ 0.40 do not allow the insertion reaction to take place due to the presence of monovalent copper combined with the lack of vacancies to accommodate Li ions. In the latter case, the discharge of the lithium copper nitrides is not reversible. Keywords: Nickel nitrides, Lithium insertion, Negative electrode, Lithium batteries

The high temperature reactions of 1 M LiPF6 EC:DEC and LiCoO2, Li(Ni1/3Co1/3Mn1/3)O2 (NCM) or Li(Ni0.8Co0.15Al0.05)O2 (NCA) charged to 4.2 V and 4.4 V, respectively, were studied by accelerating rate calorimetry (ARC). The results indicate that NCM shows better thermal stability than both LiCoO2 and NCA. The state-of-the-art NCA sample shows better safety properties than LiCoO2. The reactivity of the samples depends on the electrolyte:active material ratio used during ARC testing. Electrode materials charged to 4.4 V are more reactive than the electrode materials charged to 4.2 V. These results should be useful for Li-ion battery researchers interested in maximizing the safety of high energy density cells and also as a benchmark for other researchers using ARC. Keywords: Lithium-ion battery safety, Accelerating-rate calorimetry, Positive electrode materials

In this study, a novel method was presented to improve the cycle performance of the spinel LiMn2O4 This method is quite different from the traditional way of coating LiMn2O4 particle itself with inorganic and organic compounds. First we covered the current collector with the mixture of LiMn2O4 particle, conductive agents and binders, and then deposited an aluminum film onto it by means of vacuum evaporation. The pure electrode and the modified electrode were investigated using a combination of scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and charge–discharge tests. The enhancement of the capacity retention of modified electrode is significant, maintaining 93.5% of the maximum capacity after 200 cycles at charge–discharge rate of C/2, while pure electrode only 63.7%. It was found that the improvement of cycling performance is greatly ascribed to the good electrical conductivity of aluminum film deposited on the surface of spinel LiMn2O4. Keywords: Deposited, Aluminum film, Capacity retention, Electrical conductivity

The recent announcement of the launch in the market of a new type of lithium-ion battery has instilled new life in the R&D of innovative electrode materials and, in particular on multi-component, tin-based, nanostructured lithium metal storage anodes. Following this trend, we have synthesized by high energy ball milling a Sn–Co–C ternary compound of composition supposedly similar to that used in the new commercial battery. We have tested this material as an electrode in a single lithium cells, as well as in an original, complete lithium-ion battery configuration. The results demonstrate the promising feature of this compound as innovative, high-capacity lithium-ion electrode. Keywords: Tin, Alloy, Composite, Ball milling, Lithium, Battery

We obtained pure nanosized α-LiFeO2 by a simple and quick method involving the reaction between goethite, lithium hydroxide and lithium nitrate at temperatures as low as 523 K. Unlike the known limited electrochemical activity of this polymorph, cells based on our nanosized electrode provided a remarkable high capacity in the first cycles and showed a good cycling life, due to its nanosized character and adequate morphology to enhance lithium insertion/deinsertion. Capacity values when cycling in the 1.5–4.5 V range are up to 150 mAh g−1 in the 50th cycle. To our knowledge, the capacity values and its retention upon cycling are the best reported for this polymorph in an un-doped state. Keywords: α-LiFeO2, Lithium ion batteries, Positive electrode, Nanosized materials, Goethite

Lithium-rich Li1.05Mn2O4 hollow nanospheres have been successfully prepared by air-calcining lithiated MnO2 precursor at a low temperature of 550 °C, which was synthesized by chemical lithiation of hollow MnO2 nanospheres with LiI at 70 °C for 12 h. The lithium-rich Li1.05Mn2O4 hollow nanospheres exhibit an excellent cycling stability and rate capability as a cathode material for rechargeable lithium batteries: it maintains 90% of its initial capacity after 500 cycles, and keeps 70% of the reversible capacity at 0.1 C rat, even at 15 C rate. Keywords: Hollow nanospheres, LiMn2O4, Spinel, Lithium-ion battery

Using a commercially available LiCoO2 as starting material, a surface-modified cathode material was obtained by coating it with a nano layer of amorphous carbon. The carbon-coated LiCoO2 was characterized by X-ray diffraction analysis, scanning electronic microscopy, transmission electronic microscopy, electrochemical impedance spectroscopy and measurement of charge/discharge behavior. Results show that the carbon-coated LiCoO2 displays marked lower charge transfer resistance, higher lithium ion diffusion coefficient and much better rate capability than the original LiCoO2. It also indicates promising application of lithium ion batteries in the areas requiring charge and discharge at high rate. Keywords: Lithium ion battery, LiCoO2, Carbon coating, Rate capability

Microarray electrodes of LiMn2O4 and Li4/3Ti5/3O4 were prepared on a glass substrate using a sol–gel method. The prepared LiMn2O4 and Li4/3Ti5/3O4 microarray electrodes were characterized with scanning electron microscopy, Raman spectroscopy, and cyclic voltammetry. Using a polymer-gel electrolyte, lithium ion microbattery of Li4/3Ti5/3O4/polymer-gel/LiMn2O4 (cell area: 6.6 × 10−2 cm2) was successfully constructed. The microbattery operated reversibly at 2.5 V, and the discharge capacity was 300 nA h, which corresponded to an energy density of 11 μW h cm−2. Keywords: Lithium batteries, Sol–gel, Microelectrodes

The performance of the SrCo0.8Fe0.2O3−δ(SCF)–La0.45Ce0.55O2−δ(LDC) composite cathodes was studied in this paper. The composite cathodes were prepared by screen-printing, and then sintered at 1200 °C for 2 h. Electrochemical impedance spectroscopy (EIS) and cathodic polarization test were carried out to investigate the electrochemical properties of the composite cathodes. The results showed that the composite cathodes had superior electrochemical performance compared to that of the pure SCF cathodes. Through optimizing the structures of composite cathodes, the cathodic overpotential of triple-layer SCF–LDC composite cathodes was only 23 mV at 0.3 A cm−2. The specific ohmic resistance, charge transfer resistance and gas phase diffusion resistance of the triple-layer SCF–LDC cathodes were the lowest for the SCF–LDC composite cathodes, and they were 0.1 Ω cm2, 0.01 Ω cm2 and 0.1 Ω cm2 respectively at 800 °C. The changes were attributable to the enlargement of triple phases boundary (tpb) and enhancement of the adhesion between electrode and electrolyte by adding LDC to the cathode material. Keywords: SOFC, Composite cathodes, EIS, SrCo0.8Fe0.2O3−δ–La0.45Ce0.55O2−δ, Tpb

Nanocrystalline rutile TiO2 is prepared at RT from acidic solution by sol–gel method using titanium tetraisopropoxide as precursor. Samples of varying crystallite sizes are prepared by post annealing the as synthesized rutile TiO2 at different temperatures. The absorption spectra of synthesized samples reveal a large blue shift (311 nm) vis a vis bulk rutile TiO2 (394 nm) indicating the nanocrystalline nature of the material. Electrochemical studies performed at RT show that one Li per formula unit is inserted into the nanocrystalline rutile TiO2. Variation in the voltage profiles is observed with respect to small changes in the crystallite sizes within the nanometric regime. Keywords: Nanocrystalline rutile TiO2, Sol–gel synthesis, Room temperature Li insertion

The electronic conductivity of Cu0.1-doped VOx-NTs is up to magnitude higher than that of the undoped material. Doped vanadium oxide nanotubes also exhibit significantly improved kinetic behavior and rate capability. Cu0.1-doped VOx-NTs present good electrochemical behaviors at 10 mA/g discharge current density with initial specific capacity 120.2 mAh/g. Keywords: Rechargeable magnesium battery, Doped vanadium oxide nanotubes, Electrochemical intercalation

To improve the capacity retention of LiCoO2 at 4.5 V cut-off cycling, the AlF3 as new coating material was introduced. The AlF3-coated LiCoO2 showed no large difference in the bulk structure and a uniform AlF3-coating layer whose thickness is of about 10 nm covers LiCoO2 particles, as confirmed by transmission electron microscopy. The AlF3-coated LiCoO2 delivered the similar initial discharge capacity to pristine LiCoO2 to 4.5 V versus Li. Surprisingly, the capacity retention and rate capability were greatly enhanced comparing to the pristine LiCoO2. Ac-impedance results showed that the AlF3-coated LiCoO2 has stable charge transfer resistance (Rct) on cycling. Reduced Co dissolution was also seen for the AlF3-coated LiCoO2. Keywords: AlF3 coating, Cathode materials, Impedance, Lithium secondary batteries

Pure Na2Ti6O13 phase was successfully prepared from partially washed (Na,H)TiO nanotubes and used as an insertion material for lithium ions. Results show that the structure can accommodate upto 3 mol of lithium per 1 mol of Na2Ti6O13. Accommodation of 0.5 mol of lithium per one titanium atom corresponds to the partial reduction of Ti4+ to Ti3+ and occurs several 100s of millivolts lower than typically encountered for titanium in an octahedral oxygen environment such as Li4Ti5O12. Lithium insertion into this phase was evaluated using especially in situ X-ray. Lithium insertion into Na2Ti6O13 phase includes three domains corresponding to two solid–solutions and a biphasic transition in the potential range between 1.5 V and 1.0 V vs. lithium. The process is very reversible so that after re-oxidation the structure is completely preserved. Capacity fading observed during the cycling is explained by parasitic reactions attributed to a catalytic effect of the exposed bare surface on the electrolyte degradation. Keywords: Na2Ti6O13, Titanium oxide, Anode, Lithium insertion, Li-ion batteries

A series of lithium nickel composite oxides LixNi2−xO2 (0 ⩽ x ⩽ 1) were synthesized and characterized by X-ray diffraction (XRD) measurement. As lithium content increases, the cell parameters decrease. It is found that the cell volume (V) and lithium content (x) have a good linear relationship which corresponds to a linear equation, V = 109.0366 − 7.6572x (R = −0.9999). The credibility of the linear relationship was confirmed by inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis. The electrochemical properties of LixNi2−xO2 (0.9 ⩽ x ⩽ 1) whose composition determined by the linear relationship were discussed. The oxide exhibits better electrochemical properties with x closing to 1. The linear relationship can be applied to determine the lattice composition and evaluate the electrochemical properties of LixNi2−xO2 electrode materials for lithium ion battery. Keywords: Lithium ion battery, Lithium nickel composite oxide, X-ray diffraction, Linear relationship, Lattice composition

The replacement of a toxic KCN etch step used for the preparation of efficient thin film solar cells with CuInS2 by a mixed photoelectrochemical and electrochemical anodic conditioning procedure is reported. Processing in V2+/V3+ – 4.4 M HCl redox electrolyte with specific potential ramps results in photoelectrochemical solar cells (PECS) superior to KCN etched cells after combination with an additional procedure employing anodic potential pulses. Solar-to-electrical conversion efficiencies of PECS yield η = 2.4% for KCN etched samples and of 3.3% for the new two-step treatment. X-ray photoelectron spectroscopy (XPS) and solar cell analysis show removal of Cu–S phases and formation of ordered defect compounds (OVCs) on CuInS2. After electrochemical treatment the surface is less Cu-depleted than after KCN etching attributed to a non-sulfide monovalent Cu compound. Keywords: Electrochemical etching, Photoelectrochemical solar cell, CuInS2, X-ray photoelectron spectroscopy, Corrosion

We report herein on the effect of the PVdF binder on the stability of composite LiCoO2 electrodes at elevated temperatures in 1 M LiPF6 EC/EMC solutions at open circuit conditions. The structure and morphology of composite LiCoO2 electrodes with different combinations of electrode components (LiCoO2 active material, PVdF binder, carbon black and current collector) were evaluated by Raman spectroscopy, X-ray diffraction and SEM. The content of Co ions in the electrolyte solutions was determined by ICP. A new effect was discovered, namely, a detrimental impact of the contact between PVdF and LiCoO2 on the stability of the active mass. The formation of surface Co3O4 and dissolution of Co ions at elevated temperatures is accelerated at the contact points between the active mass and the binder. The effect of water content in the electrolyte solutions on the stability of LiCoO2 was also studied. The presence of water (and/or HF) is a necessary condition for the accelerated dissolution of Co ions from the active mass. LiCoO2 oxidizes the solvents at elevated temperatures thus forming CO2. Keywords: LiCoO2 cathodes, PVdF binder, Structural degradation, Raman spectroscopy, XRD, SEM

We present a new concept hybrid electrochemical surpercapacitor technology in which the activated carbon was used as a negative electrode and a lithium-ion intercalated compound LiMn2O4 as a positive electrode in a mild Li2SO4 aqueous electrolyte. The charge/discharge process is associated with the transfer of Li-ion between two electrodes. The hybrid cell exhibits a sloping voltage profile from 0.8 to 1.8 V, and delivers an estimated specific energy of ca. 35 W h/kg based on the total weight of the active electrode materials. The cell exhibits excellent cycling performance with less than 5% capacity loss over 20,000 cycles at 10 C charge/discharge rate. The new state-of-the-art hybrid aqueous supercapacitor technology overcomes the drawbacks of electrolyte depletion during charge process of conventional hybrid supercapcitors, and also solved the major problems of poor cycling life of lithium-ion battery electrode materials in aqueous electrolyte. Keywords: Lithium-ion intercalated compound, Activated carbon, Spinel LiMn2O4, Supercapacitors, Aqueous lithium-ion batteries, Hybrid cell

The synthesis and analysis of Ag2FeO4 is described, as well as the first studies of its use as a cathode for electrochemical charge storage. Cathodes comprised of Fe(VI) salts, are capable of multiple electron reduction, and are useful for the formation of energetic Super-iron batteries. Ag2FeO4 is of compelling interest, capable not only of 3e− cathodic storage (as Fe(VI → III), but with an intrinsic availability of additional Ag(I) sites, for a total of a 5e− alkaline reduction: Ag 2 FeO 4 + 5 2 H 2 O + 5 e - → 2 Ag + 1 2 Fe 2 O 3 + 5 OH - The first IR spectra of Ag2FeO4 are presented, and compared to spectra of K2FeO4 and Ag2O. Ag2FeO4 is synthesized by dissolving K2FeO4 in aqueous Ag(I), and isolation of the precipitate. ICP analysis provides evidence of over 99% conversion from potassium to the silver salt, although chromite analysis indicates a 13% Fe(III) impurity in the Ag2FeO4 product. Ag2FeO4 is less stable than K2FeO4 or BaFeO4, at 0 °C falling in purity from 87% to 83% over a period of 1 week, and to 73% at 25 °C, although this instability may be an artifact of the higher Fe(III) impurity in the synthesized salt. Alkaline Zn anode/cathode cells are discharged. The measured Ag2FeO4 coulombic efficiency is less than that of other Fe(VI) cathodes, related to inhibition of charge transfer due to the Fe(III) impurity sites interspersed in the cathode.