Liquid Electrolyte Batteries Research Articles

Superionic glasses and glass–ceramics in the Li2S–P2S5 system for all-solid-state lithium secondary batteries

Glass-based superionic materials are among the most promising candidates for inorganic solid electrolytes applicable to all-solid-state battery systems. We have developed a variety of sulfide-based glassy electrolyte systems. This paper reviews the advantages and development of sulfide-based superionic glasses and glass–ceramics, and the application of these materials to all-solid-state battery systems. The most important advantage of glass-based electrolytes is the fact that the superionic conducting crystals are easily formed as a metastable phase from glassy materials. The heating of Li2S–P2S5 glasses results in the formation of superionic Li7P3S11 glass–ceramic. The conductivity was improved up to 5×10−3Scm−1 at room temperature by doping with other elements and optimization of the glass formation and crystallization processes. The application of these glass-based solid electrolytes to a variety of all-solid-state lithium secondary batteries is also reported, using not only typical electrode active materials such as LiCoO2 and Li4Ti5O12, but also materials that are difficult to use in liquid electrolyte batteries, such as elemental sulfur.

Remarkable Impact of Water on the Discharge Performance of a Silicon–Air Battery

Here, we report on a Si-air/ionic liquid electrolyte battery whose performance improves with small amounts of water in the electrolyte. The shift of the generation zone of the SiO(2) discharge product from the air cathode surface into the bulk region of the liquid electrolyte, caused by water addition, is demonstrated through various means. Addition of 15 vol% water leads to an increase of 40% in the discharge capacity as compared to the capacity obtained using a pure ionic liquid electrolyte. If the water content increases above 20 vol%, the Si-air cell capacity dramatically decreases. The water-ionic liquid electrolyte mixture shows a maximum in the ionic conductivity with a water content of 10 vol%. In-depth studies indicate a reduced amount of discharge product at the air electrode using 15 vol% H(2)O electrolyte. The morphology of the anode surface, as well as the developed surface film in the presence of water-containing ionic liquid, is reported. This study shows that exposing a Si-air battery to a humid environment does not result in capacity losses, but rather improves cell performance.

Aging of lithium-ion batteries

Abstract Lithium-Ion (liquid electrolyte) batteries are considered as long life and reliable systems. This paper: • introduces discussion about aging and degradation mechanism both for storage and cycling, • illustrates the proposed phenomena from results based on several years experimentation and obtained on scale one cells, • shows the behaviour of several kinds of active materials, • proposes some trends for life prediction. Aging in Li-Ion cells may mainly come from: • reactions of active materials with electrolyte at electrodes interfaces, • self degradation of active materials structure on cycling, • aging of non active components (ex: electrodes binders). These phenomena lead to energy and/or power losses. Reaction rates on depending on: • type of materials and reactivity • impurities • manufacturing processes • cell design • type of application and profile of use. On the negative electrode side the main parameters are passivation layer stability, the layer structure/composition (effect of additives in electrolyte and formation process), polluting agents. On the positive electrode side key factors seem to be the material structure evolution and organic solvent oxidation. These phenomena are highly dependent of voltage and temperature. So far, according to experimentation for electric (EV) and hybrid (HV) vehicles applications, using scale 1 cells built with nickel based positive material the results show: • more than 1 200 deep cycle (80% d.o.d. EV cycle) with only few percent of energy and power losses, • more than 500 000 shallow cycles (3% d.o.d. HV cycle) with negligible power losses, • 2 years of storage testing at full charge and various temperature (20 °C/40 °C/60 °C) leading to a life expectation of 10 years for EV applications and 15 years for HV applications.

Research on the industrial utilization of and combustion of clean desulphurized briquette

This study demonstrates the effect of polydopamine coating on separator membranes used in liquid electrolyte batteries as a function of membrane porosity. We select two typical separators that differed only in porosity. High-porosity (16H) and low-porosity (16L) separators are coated with polydopamine by simple dip-coating. Their properties are evaluated via scanning electronic microscopy (SEM) and determining the water contact angle, Gurley number, ionic conductivity, and uptake volume of liquid electrolyte. In addition, the effect of polydopamine coating on electrochemical properties is tested using CR2032 coin-type half-cells (LiMn2O4/Li metal). With enhanced hydrophilic properties of surfaces as keeping pore structures, both of polydopamine coated high and low porous separators show enhanced rate capability and cell performance compared to uncoated versions. The effect of polydopamine coating is greatly enhanced in the low-porosity separators, with up to 40% increase in power capability (at 5 C rate) and a 290% increase in cycle performance (after 500 cycles, at C/2 rate), compared to the high-porosity type (13% increase in power capability, 43% increase in cycle performance).

Recent developments and future prospects for lithium rechargeable batteries

Possible future developments of lithium rechargeable batteries are discussed. Lithium ion liquid electrolyte batteries are now well established, with energy densities of up to around 150 Wh kg −1. There are prospects of increases in the energy density to perhaps 200–250 Wh kg −1 by using new cathode materials (lithium nickel cobalt oxide) and light weight construction. High power cells make it possible for these batteries to find new uses, e.g. in military applications. Some new materials could reduce the cost, which might make lithium rechargeable batteries economic for electric vehicles.

Solid polymer electrolytes for lithium cells

This paper reports on ionic conductivity, mechanical characteristics, thermal stability, and electrochemical stability of solid polymer electrolytes (SPEs) that use a cross-linked poly(ethylene oxide) and a cross-linked ethylene oxide copolymer both containing a plasticizer. We obtained the SPEs that have a high ionic conductivity of 2.4 × 10 −3 S cm −1 at 20 °C, a mechanical strength that creates no problems in practical use, and higher thermal stability than liquid electrolytes. Batteries using these SPEs were manufactured and submitted to various tests. The results showed that the low-temperature and rate characteristics of these batteries were comparable with those of liquid electrolyte batteries. The results of loading, bending and twisting tests indicated that no internal shorting of the batteries occurred. These batteries did not swell at high temperatures at which liquid electrolyte batteries usually do.

A thin layer, solid-state, primary Li�Ag2CrO4 polymer battery

The majority of lithium polymer batteries under development use intercalation compounds as cathode materials [1]. The lithium-intercalation compound combination benefits from high cyclability, but suffers from sloping charge and discharge voltage profiles. In previous work we have described some new types of lithium polymer batteries based on nonintercalation cathode materials which involved LilAg2WO 4 or LilCuWO4 couples [2]. The use of these electrochemical systems in combination with a highlyconducting polymer electrolyte membrane, allowed the fabrication of thin-layer, laminated batteries having very interesting features, such as flat, highvoltage discharge curves, high-rate discharge capability and a limited but significant cycling life. Considering these promising results, we have extended the study by considering the LilAg2CrO4 electrode system, which, although used in liquid electrolyte batteries [3], to our knowledge has never been tested in solid-state, lithium polymer electrolyte batteries. Silver chromate is expected to be more promising cathode material than silver tungstate both in terms of cost and of specific capacity. The results describing the fabrication of this new type of LilAg2CrO 4 polymer battery and its electrochemical evaluation, are illustrated and discussed in this work.

Defect Spinels in the System Li—Mn—O. Chemistry and Lithium Insertion

AbstractSpinel phases Li-Mn-C with Li/Mn ratios between 0.35 and 0.8 were synthesized. The relationships between composition, manganese valence, vacancy fraction and electrochemical capacity are described using a new composition-valence phase diagram. Electrochemical performances in lithium batteries are compared. The best materials showed constant capacit> 140 Ah/kg in the range 3.5/2 V in liquid electrolyte batteries up to 20 cycles, without the usual capacity drop observed in stoichiometric LiMn204.

Recent progress in the development of solid electrolyte batteries

Solid electrolyte batteries may be loosely defined as power sources within which the transfer of the ionic species between the cathode and anode plates occurs by migration through a as opposed to a liquid phase. Within this definition one may include those systems which have, for example, a gaseous depolarizer and which can not therefore be classified in the strictest sense as all-solid batteries. Again, it should be pointed out that the use of the term solid does not imply that such systems may be thought of as dry. Indeed, there is a considerable volume of evidence, which will be mentioned later, to indicate that no electrolyte system which has been developed to date can operate without the presence of a trace liquid phase. In spite of these limitations, however, electrolyte systems have a number of quite unique advantages which can not be as readily fulfilled by present day state of the art liquid electrolyte units. For example, such systems can be assembled into extremely rugged configurations and may thus be used in applications which require a battery that will withstand acceleration forces of the order of several thousand times that due to gravity coupled with spin rates of several hundred revolutions per second. Further, with liquid electrolyte batteries one is limited to that range of temperatures between which the electrolyte freezes and boils and also with loss of the electrolyte on long term standby processes of evaporation and leakage. To a large extent such problems may be avoided by the use of electrolytes though for those systems which utilize a gaseous depolarizer one also encounters problems associated with the sealing of the unit. Perhaps the most the use of a miniature batteries important advantage associated with electrolyte is the ease with which may be produced. As a general statement it is true to say that the power requirements of electronic devices are continually being reduced by the development of more sophisticated micro-electronic circuit components and hence if the advances made in these areas are to be utilized to the fullest extent there must be a corresponding reduction in the size of the power source. With the present day liquid electrolyte systems, however, the problem of containment of the liquid phase constitutes an increasingly greater problem