Nickel positive electrode for fiber battery
Disclosed is a nickel positive electrode for a fiber battery having a long life duration, and also being enabling a high output and high capacity to be attained. For this purpose, the nickel positive electrode for a fiber battery is obtained by coating a carbon fiber with nickel, then causing a cathodic polarization in a nickel nitrate bath using the nickel-coated carbon fiber as a cathode, and then immersing the precipitate, which was deposited on the surface of the carbon fiber by the cathodic polarization, in an aqueous caustic alkali solution.
1. A fiber nickel positive electrode comprising:
a carbon fiber; and
an active material layer of NiOOH disposed on the carbon fiber,
wherein the active material layer has a layered structure that consists of:
a first active material layer made of γ-NiOOH and disposed on the carbon fiber; and
a second active material layer made of β-NiOOH and disposed on the first active material layer.
2. The fiber nickel positive electrode according to claim 1 , wherein a monofilament constituting the carbon fiber has a diameter of 5 to 100 μm.
3. The fiber nickel positive electrode according to claim 1 , wherein the carbon fiber is formed as a bundle of 1,000 to 2,000 monofilaments.
4. The fiber nickel positive electrode according to claim 1 , wherein the carbon fiber is formed as a bundle of 2 to 10 twisted monofilaments.
5. The fiber nickel positive electrode according to claim 1 , wherein the carbon fiber has a nickel-plating layer thereon, the nickel-plating layer having a thickness of 0.5 to 15 μm.
6. A secondary battery comprising:
the fiber nickel positive electrode according to claim 1 ;
a negative electrode containing a hydrogen storage alloy;
an aqueous electrolyte; and
a separator.