Secondary battery with aqueous electrolytes

Zinc/carbon and alkaline/manganese cells are primary battery systems lead, nickel/cadmium, and nickel/metal hydride accumulators are secondary batteries with aqueous electrolyte solutions. Their per-... 

Eurukawa and co-workers [81] state that PANI is an interesting material because it is not only an ECP but is also a good material to use as an electrode of a secondary battery with aqueous or non-aqueous electrolytes. PANI polymerised from aniline in an aqueous acid solution is converted to several forms with different electrical properties by acid/base treatments and oxidation/reduction. The as-polymerised form gives high electrical conductivity ( 5 S/cm). It becomes insulating when treated with an aqueous alkaline solution or is reduced electrochemically in an aqneons acid solution. Reduced-alkali-treated PANI is also insulating and is unstable in air its colour changes from white to blue upon exposure to air. PANI doped with electrolyte anions is obtained by electrochemical oxidation [82]. It was found in this work to be a new conductivity form (o = 5.8 S/cm). Recently, a secondary lithium battery with a reduced alkali pellet as the cathode, and non-aqueous electrolytes has been developed as a power source of memory back up and a maintenance-free power source combined with a solar battery. 

They have outstanding properties in comparison with conventional secondary batteries with aqueous acidic or alkaline electrolytes including nickel / cadmium, nickel / metal hydride and lead-acid secondary cells. The features of LIBs are as follows. 

T. Zhang, N. Imanishi, S. Hasegawa, A. Hirano, J. Xe, Y. Takeda, O. Yamamoto, N. Sammes, Li/polymer electrolyte/water stable lithium-conducting glass ceramics composite for hthium-air secondary batteries with an aqueous electrolyte , J. of Electrochem. Soc., 155,A965-A969,2008. 

Fabrication of a battery or a cell determines how the device will function and how much it will cost to construct it. Several primary cells with aqueous electrolytes seem to use a single electrodes arranged in parallel or concentric configuration. Specific construction of this type of cell includes cylindrical or bobbin button, and coin. Small secondary cells use a wound or jelly roll construction feature, in which long thin electrodes are wound into a cylinder and placed in a metallic housing or container. This particular cell construction yields higher power density, but it... 

All lithium based batteries use nonaqueous electrolytes because of the reactivity of lithium in aqueous solution and because of the electrolyte s stability at high voltage. The majority of these cells use microporous membranes made of polyolefins. In some cases, nonwovens made of polyolefins are either used alone or with microporous separators. This section will mainly focus on separators used in secondary lithium batteries followed by a brief summary of separators used in lithium primary batteries. 

In considering the selection of anodes for high energy density (HED) storage (or secondary) batteries (SB), we note that there are some 19 metals whose free-energy density (TED) of reaction with oxidants such as O2, Cl2, and F2 are higher than those of Zn with the same oxidants. Most of these metals react violently with water. The remainder are passivated by water. Therefore other electrolytes must be considered for these metals, based on non-aqueous, molten salt, or solid-state ionic conductors. Much experimental work has been carried out during the last two decades on primary and secondary batteries based on anhydrous electrolytes, aimed at utilization of the active metals. 

Ni-Cd cells — The nickel-cadmium cell is a secondary - battery that has a nominal cell potential of 1.20-1.25 V. The negative electrode comprises nickel hydroxide-nickel oxyhydroxide, the positive electrode is cadmium, and the electrolyte solution is based on aqueous potassium hydroxide (KOH, 32% in water). At the anode, the discharge reaction is the oxidation of cadmium metal to cadmium hydroxide with the release of two electrons [i] ... 

Nakanishi [5] prepared siloxane-modified cyclic carbonates, (VI), that when combined with a nonaqueous solvent and an electrolyte salt formed a non-aqueous electrolytic solution that was used to construct a secondary battery having improved temperature and cycle properties. 

The greatest development of the last ten years has been the infiltration into the market of ambient-temperature hthium batteries with a non-aqueous electrolyte. Again, the attraction of such cells is their high energy density combined with a high cell voltage, 2.0—4.0 V. While they have been developed for many applications both primary and secondary, the greatest success has been with small primary cells for microelectronic circuitry. 

Lithium-Metal Salt secondary batteries are analogous to the Lithium-seawater primary battery [3]. A Li -ion solid electrolyte separates a nonaqueous anolyte and an aqueous cathode. For example, a Lithium anode with a carbonate anolyte and an aqueousFe(CN)g /Fe(CN)g cathode has been shown to give aflat voltage F 3.4 V with an efficiency that increases with the molar ratio of iron cyanide in the cathode solution [27]. This promising approach requires development of a Li-ion solid electrolyte having a (Tli > 10 8/cm at room temperature that is stable to an acidic cathode solution and is not reduced by contact with a Li° dendrite on the anode side. 

In battery systems based on aqueous electrolyte, water decomposition, which occurs above a cell voltage of 1.23 V, is such an unavoidable secondary reaction. But under certain conditions the resulting water loss can be avoided, and the system is used as a sealed one, as achieved with sealed nickel/cadmium, nickel/hydrogen, and nickel/metal hydride batteries. In lead-acid batteries corrosion is an additional unwanted secondary reaction with the consequence that lead-acid batteries cannot be made virtually sealed, but must have a valve, and a certain water loss cannot be prevented. 

Most of the other conventional types of secondary batteries use an aqueous alkaline solution (KOH or NaOH) as the electrolyte. Electrode materials are less reactive with alkaline electrolytes than with acid electrolytes. Furthermore, the charge-discharge mechanism in the alkaline electrolyte involves only the transport of oxygen or hydroxyl ions from one electrode to the other hence the composition or concentration of the electrolyte does not change during charge and discharge. 

The primary and secondary batteries based on lithium use nonaqueous electrolytes because of the reactivity of Hthium with aqueous solutions. 

Lithium ion secondary batteries (LIBs) with non-aqueous electrolytes were successfully developed and introduced into the market for the first time in 1991 by Sony Corporation. 

The same configuration of the hybrid Pb02/MHj. secondary battery has been applied with gel electrolytes instead of aqueous electrolyte (cf. Sections 11.7 and 11.9.1) [56] to solve some issues on conventional batteries maintenance cost and acid stratification for the lead-acid battery, high self-discharge and short life cycles for high current discharge for nickel-metal hydride battery. In addition, gel electrolytes offer advantages such as leak proof, maintenance-free and corrosion-free. 

Initial development of ambient secondary lithium batteries was based on the primary lithium systems described in Chapter 4, consisting of a lithium metal negative, a non-aqueous lithium ion conducting electrolyte and a positive electrode material which could undergo a reversible electrochemical reaction with lithium ions ... 

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