Batteries metal hydride-based

High-power lithium-ion batteries are promising alternatives to the nickel metal hydride batteries which are currently used for energy storage in hybrid electric vehicles (HEVs). Currently, Li(Ni,Co)02-based materials are the most widely studied cathode materials for the high-power lithium-ion batteries [1-4]. Although Li(Ni,Co)02-based materials meet the initial power requirement for the HEY application, however, it has been reported that they... 

Batteries based on metal hydrides show the promise of becoming power sources for electric vehicles in the future (Ovshinsky et al., 1993). Such a battery constructed of nontoxic recyclable materials can operate at room-temperature. 

A nickel-metal hydride rechargeable battery for laptop computers is based on the following chemistry ... 

The manufacture of secondary batteries based on aqueous electrolytes forms a major part of the world electrochemical industry. Of this sector, the lead-acid system (and in particular SLI power sources), as described in the last chapter, is by far the most important component, but secondary alkaline cells form a significant and distinct commercial market. They are more expensive, but are particularly suited for consumer products which have relatively low capacity requirements. They are also used where good low temperature characteristics, robustness and low maintenance are important, such as in aircraft applications. Until recently the secondary alkaline industry has been dominated by the cadmium-nickel oxide ( nickel-cadmium ) cell, but two new systems are making major inroads, and may eventually displace the cadmium-nickel oxide cell - at least in the sealed cell market. These are the so-called nickel-metal hydride cell and the rechargeable zinc-manganese dioxide cell. There are also a group of important but more specialized alkaline cell systems which are in use or are under further development for traction, submarine and other applications. 

The catalysts for oxygen reduction and oxygen oxidation are materials based on substances like Co, Ni, Fe, Mn [16, 19]. One of new applications of oxygen reduction catalysts is air-metal hydride accumulator. Electrodes based on La0.1Cao.4Co03, La0. Cao.,jMn03 [18] are used in this battery. The electrodes of similar composition could be used in SOFC. An insertion of the oxides in their composition (CuO for example) leads to increasing the conductivity of system and efficiency of catalyst [30]. 

Lead-acid, nickel-iron (Ni-Fe), nickel-cadmium (NiCd), and nickel-metal hydride (NiMH) batteries are the most important examples of batteries with aqueous electrolytes. In lead-acid batteries, the overall electrochemical reaction upon discharge consists of a comproportionation of Pb° and Pb4+ to Pb2+. All nickel-containing battery reactions are based on the same cathodic reduction of Ni3+ to Ni2+, but utilize different anodic reactions providing the electrons. Owing to toxicity and environmental concerns, the formerly widely used Cd°/Cd2+ couple (NiCd cells) has been almost entirely replaced by H/H+, with the hydrogen being stored in a special intermetallic compound (NiMH). 

Outlook for rare earth based metal hydrides and NiMH rechargeable batteries... 

The rare earth based metal hydrides AB5 have proven to be best suited for use in the negative electrode in NiMH batteries. The market demand for the nickel-metal hydride battery is high because of the rapid demand for portable electronics goods such as video cameras, shavers, power tools, cellular phones, lap-top computers which use high performance batteries. 

Both Ni/MH and Li-ion batteries do contain hazardous materials. Niekel/metal hydride battery packs, of course, contain nickel, which is a suspected carcinogen in some forms. However, the only hazardous material in a Ni/MH battery, as defined by federal regulations, is the potassium hydroxide (KOH)-based electrolyte (corrosive). The only characteristic hazard of any consequence for the electrode materials in these batteries is toxicity. The hazard level is determined by a test called the toxicity characteristic... 

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