Improved NiMH performance by a surface treatment that creates magnetic Ni-clusters

• A surface treatment method has been developed to activate the surface of an AB(5) type (La-20 Ce-7 Pr-1 Nd-4 Al-2 Mn-5 Co-6 Ni-55) alloy. In the process the surface is covered with a porous surface layer containing needle shaped rare earth hydroxides after etching by a potassium hydroxide solution. TEM studies show in addition the presence of a denser surface oxide layer with embedded Ni containing clusters covering the bulk alloy. The magnetic properties of the alloy powders change with the surface treatment. In addition to a paramagnetic component of the bulk alloy, surface treated alloy also displays superparamagnetic and ferromagnetic properties. In electrochemical half-cell tests, the alloy shows better high-rate dischargeability with increasing presence of magnetic clusters in the metal hydride particles surface.

Ämnesord

NATURVETENSKAP  -- Kemi -- Oorganisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Inorganic Chemistry (hsv//eng)

NATURVETENSKAP  -- Fysik -- Annan fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Other Physics Topics (hsv//eng)

Nyckelord

Metal hydrides

NiMH batteries

Surface treatment

Ni clusters

Discharge kinetics

Rare earths hydroxides

Inorganic Chemistry

oorganisk kemi

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