Aqueous Lithium-ion Batteries Research Articles

Synthesis of LiCoO2 by l-apple acid assisted sol–gel method and its electrochemical behavior in aqueous lithium-ion battery

The synthesis process of LiCoO2 prepared by l-apple acid (l-HOOCCH(OH)CH2COOH) assisted sol–gel method is studied by using Fourier transforms infrared spectroscopy, mass spectroscopy, simultaneous thermogravimetric and differential thermal analysis, X-ray diffraction analysis, and elemental analysis. The results show that lithium and cobalt ions are trapped homogeneously on an atomic scale throughout the precursor. Lithium carbonate and Co3O4 are intermediate products during heat treatment of the precursor. Moreover, the kinetics for formation of LiCoO2 by l-apple acid assisted sol–gel method is faster than the case of the conventional solid-state reaction between lithium carbonate and Co3O4. In comparison with the solid-state reaction, the sol–gel method significantly shortens the required reaction time for synthesizing LiCoO2, and also reduces the particle size. In the electrochemical test, it is found that the specific discharge/charge capacities as well as the coulomb efficiency substantially increase with increasing the calcination temperature. It is considered that LiCoO2 with a good-layered structure facilitates the insertion and de-insertion of lithium ions in aqueous electrolyte. As a result, the combination of the sol–gel method with proper calcination processes is highly successful in producing LiCoO2 powders with large specific capacity and good cycle performance in aqueous lithium-ion battery.

Promising vanadium oxide and hydroxide nanostructures: from energy storage to energy saving

The great energy demand for fossil fuels impacts air pollution and water pollution, which significantly influences human life today, and thus efficient utilization of energy has directed a global trend towards a diversified energy portfolio, particularly focusing on energy storage and saving applications. Owing to their special structural characteristics, vanadium oxides have received particular interest for efficient energy utilization, and the search for new kinds of vanadium oxides in the applications of the energy issues has been highlighted in recent years. This review surveys recent advances in tackling energy utilization issues, such as organic electrolyte or aqueous electrolyte lithium-ion batteries (LIB), by the development of vanadium oxide nanostructures, as well as energy-saving applications, via regulating the desired structure and morphology characteristics of vanadium oxides. The nanoarchitectured vanadium oxides with valence state from +3 to +5 all seem ripe for further development for the organic-electrolyte LIB application with improved energy density and cycling performance. In addition, solution-based synthesis gives a facile and inexpensive route to grow and assemble their nanoarchitectures for organic-electrolyte LIB applications. Moreover, although the application of vanadium oxides in aqueous LIB is still in its infant stage, controlling the morphology and structure of vanadium oxides also plays a vital role in the improvement of the aqueous LIB performance. Furthermore, the energy-saving application of vanadium oxides, which arises from the smart switching properties, bring us drastic changes in electrical conductivity and near-IR optical properties for the energy-saving application as the “smart window” coatings. The challenges and ongoing research strategies of the application of vanadium oxides for efficient energy utilization are also discussed in this review article.

From synthetic montroseite VOOH to topochemical paramontroseite VO2 and their applications in aqueous lithium ion batteries

Synthetic montroseite VOOH has been successfully prepared via a simple template-free hydrothermal route on a large scale for the first time-after sixty years of delay. The as-obtained sample shows a hierarchical morphology of urchin-like nanoarchitecture with hollow interiors consisting of well-crystalline nanorods standing vertically on the shell surface. Time-dependent experiments illustrated that these hierarchical hollow nanourchins were formed through the hydrolysis-driven Kirkendall effect coupled with a new-phased vanadium oxyhydroxide V(10)O(14)(OH)(2) precursor templated approach. Meanwhile, the as-obtained VOOH hollow nanourchins could convert topochemically to paramontroseite VO(2) without altering the size and original appearance during the annealing process due to the extreme structural similarity revealed by crystal structure analysis. Furthermore, the improved electrochemical performance of both montroseite VOOH and paramontroseite VO(2) hierarchical hollow structures toward Li uptake and release verifies their potential applications as anode materials in aqueous lithium ion batteries. These improved electrochemical properties could be ascribed to the synergetic effect of the microscopic tunneled crystal structure and macroscopic hollow morphological features, which provide the easy infiltration of electrolyte, short diffusion lengths for lithium ions and electron transport as well as sufficient void space to buffer the volume change.

Novel Flowerlike Metastable Vanadium Dioxide (B) Micronanostructures: Facile Synthesis and Application in Aqueous Lithium Ion Batteries

Novel flowerlike VO2 (B) micro-nanostructures assembled by single-crystalline nanosheets have been successfully synthesized via a hydrothermal route using polymer polyvinyl pyrrolidone (PVP, K30) as capping reagent. Detailed proofs indicated that the process of crystal growth was dominated by a nucleation and growth, self-assembly, and then Ostwald ripening growth mechanism. For the first time, the flowerlike micro-nanostructures VO2 (B) was applied as the active material into aqueous lithium ion battery applications, which showed improved electrochemical properties with the first discharge capacity reaching 74.9 mAhg−1, a quite outstanding value for aqueous lithium ion battery systems in light of previous reports (usually <65 mAhg−1). In addition, corresponding VO2 (B) nanostructures with better crystallinity were obtained by calcining the precursor of flowerlike VO2 (B) structures. The post-treated flowerlike VO2 (B) electrode shows fascinating advantages in electrochemical properties with the first discharge capacity reaching 81.3 mAhg−1, which is higher than that of the flowerlike VO2 (B) sample before annealing. Furthermore, we have investigated the electrochemical intercalation and deintercalation properties with Li+ the synthesized VO2 (B) nanobelts and carambola-like VO2 (B) structure. The unique flowerlike structure plays a basic role in the morphology requirement to serve as transport paths for lithium ion in aqueous lithium ion batteries. It was observed that the morphologies and crystallinity of the synthesized products had an evident influence on the electrochemical intercalation and deintercalation properties with lithium ions.

Performance of LiCoO2 as Aqueous Lithium-ion Battery Electrodes

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Electrochemical behavior of LiCoO 2 as aqueous lithium-ion battery electrodes

Despite the large number of studies on the behavior of LiCoO 2 in organic electrolytes and its recent application as a positive electrode in rechargeable water battery prototypes, a little information is available about the lithium intercalation reaction in this layered compound in aqueous electrolytes. This work shows that LiCoO 2 electrodes can be reversibly cycled in LiNO 3 aqueous electrolytes for tens of cycles at remarkably high rates with impressive values specific capacity higher than 100 mAh/g, and with a coulomb efficiency greater than 99.7%. Stable and reproducible cycling measurements have been made using a simple cell design that can be easily applied to the study of other intercalation materials, assuming that they are stable in water and that their intercalation potential range matches the electrochemical stability window of the aqueous electrolyte. The experimental arrangement uses a three-electrode flooded cell in which another insertion compound acts as a reversible source and sink of lithium ions, i.e., as the counter electrode. A commercial reference electrode is also present. Both the working and the counter electrodes have been prepared as thin layers on a metallic substrate using the procedures typical for the study of electrodes for lithium-ion batteries in organic solvent electrolytes.

Electrochemical fabrication of anatase TiO 2 nanostructure as an anode material for aqueous lithium-ion batteries

Nanostructured titanium oxide films are fabricated directly by an anodic electrodeposition strategy at an aqueous TiCl 3 solution. Surface morphology shows that the deposited films are consisted of fine particles having 15–25 nm in diameter. Annealing temperature influences both the crystal structure and the electrochemical performance of the deposited titanium oxide. When the annealing temperature exceeds 300 °C, the poorly crystalline titanium oxide converts into anatase phase. Cyclic voltammograms (CVs) show that the anatase titanium oxide films exhibit reversible insertion/de-insertion of lithium ion in an aqueous LiOH electrolyte. The formation of lithiated titanium oxide is confirmed from an X-ray photoelectron spectroscopy. An optimal annealing temperature is found to be about 400 °C in terms of the CV peak current density. In addition, the diffusion coefficient of lithium ion in cathodic process (1.6 × 10 −15 cm 2 s −1) is higher than that of anodic process (9.4 × 10 −16 cm 2 s −1), probably due to the formation of higher O–Li bond strength during the lithium insertion.

Electrochemical properties of rechargeable aqueous lithium ion batteries with an olivine-type cathode and a Nasicon-type anode

Rechargeable aqueous lithium ion batteries have been developed by using olivine LiMn 0.05Ni 0.05Fe 0.9PO 4 as cathode material, Nasicon LiTi 2(PO 4) 3 as anode material, and saturated Li 2SO 4 solution as electrolyte. The cycling performance and rate capability of these batteries have been investigated. At a current density of 0.2 mA/cm 2, the initial discharge capacity of the battery was approximately 103.9 mAh/g, and the potential plateau was located at 0.92 V. The rate capability of aqueous electrolyte was found to be preferable to that of organic electrolyte. Such inexpensive, secure and high rate rechargeable lithium ion battery should have a potential for use in many applications.

Synthetic paramontroseite VO2 with good aqueous lithium–ion battery performance

Synthetic paramontroseite VO(2) has been successfully obtained using a simple chemical reaction route for the first time after fifty years; the paramontroseite phase shows a conducting property and good aqueous lithium ion battery performance.

Electrochemical performance of Li1−x NaxV3O8 electrodes in lithium sulfate-water-ethanol system

A series of Li1−xNaxV3O8 materials was prepared by solution reaction followed by calcination method and their electrochemical performances in 2 M Li2SO4-water-ethanol solution as negative electrodes for aqueous electrolyte lithium ion battery were studied and compared each other. X-ray diffraction analysis revealed that partially substituting sodium for lithium in LiV3O8 could increase the interlayer distances of (100) plane. Cyclic voltammetric experiments have demonstrated that the Li+ insertion and extraction kinetics of Li0.7Na0.3V3O8 is superior to that of LiV3O8. Charge/discharge results showed that the discharge specific capacity of Li0.7Na0.3V3O8 electrode is higher than that of LiV3O8 electrode.

LiV 3O 8: characterization as anode material for an aqueous rechargeable Li-ion battery system

The electrochemical characteristics of LiV 3O 8 have been investigated with respect to its use as anode material in a new type of rechargeable battery system. LiV 3O 8 reversibly intercalated/deintercalated Li + cations at potentials below the evolution potential of hydrogen in a neutral aqueous solution. Thus, it could be used as anode material in an aqueous battery system without causing the kinetic electrolysis of water. A battery cell consisting of a combination of a LiCoO 2/LiNi 1−xCo xO 2 solid solution (i.e. LiNi 0.81Co 0.19O 2) as cathode material, LiV 3O 8 as anode material and a 1 M-Li 2SO 4 (or LiCl) aqueous solution as electrolyte was constructed. With an output voltage of 1–1.2 V, a total capacity of about 45 mAh/g (weight of anode+cathode) could be obtained. Concerning the stability, 70% of the discharge capacity remained after 30 charge/discharge cycles. The loss in capacity is attributed to a deterioration of the crystal structure. The results indicate the possibility for the development of a safe and low-cost aqueous lithium ion battery.

Secondary aqueous lithium-ion batteries with spinel anodes and cathodes

Abstract Secondary aqueous lithium-ion batteries with spinel Li 2 Mn 4 O 9 or Li 4 Mn 5 O 12 as the anode and LiMn 2 O 4 as the cathode are investigated. The aqueous electrolyte contains 6 M LiNO 3 and 0.0015 M OH − . The Li 2 Mn 4 O 9 /LiNO 3 /LiMn 2 O 4 and Li 4 Mn 5 O 12 /LiNO 3 /LiMn 2 O 4 aqueous cells deliver approximately 100 m Ah g −1 capacity at an average voltage of 1–1.1 V. This aqueous lithium-ion system eliminates safety concerns and offers considerably cost-effective technology for manufacturing.