An electrochemical apparatus, including an electrolyte and a positive electrode, where the electrolyte includes ethylene carbonate and propylene carbonate, the positive electrode includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, and the positive electrode active material layer includes a positive electrode active material, where percentages of ethylene carbonate and propylene carbonate satisfy a specific relationship, and under an X-ray diffraction (XRD) test, a peak intensity I.sub.003 of plane 003 of the positive electrode active material layer and a peak intensity I.sub.104 of plane 104 of the positive electrode active material layer satisfy a specific relationship. With the above configuration, the electrochemical apparatus of this application shows excellent performances, especially the high-temperature floating charge performance.

The positive active material for a rechargeable lithium battery includes a composite material of a microporous carbon-based material and a lithium composite compound and a carbon layer on the surface of the composite material.

A battery comprising an acidified metal oxide (“AMO”) material, preferably in monodisperse nanoparticulate form 20 nm or less in size, having a pH<7 when suspended in a 5 wt % aqueous solution and a Hammett function H.sub.0>−12, at least on its surface.

A battery system includes a nickel hydride battery and an electronic control unit. The electronic control unit is configured to store data indicating a corresponding relationship between an elapsed time from start of use of the nickel hydride battery and a memory quantity. The data are data determined in a classified manner individually for each of conditions of use that are defined in such a manner as to include an open circuit voltage and a temperature. The electronic control unit is configured to sequentially calculate, with reference to the data, the memory quantity within a time when classification of the conditions of use does not change. The memory quantity is a quantity indicating an amount of change in voltage resulting from a memory effect. The electronic control unit is configured to estimate a current memory quantity of the nickel hydride battery by integrating the calculated memory quantity.

A battery system includes a nickel hydride battery and an electronic control unit. The electronic control unit is configured to store data indicating a corresponding relationship between an elapsed time from start of use of the nickel hydride battery and a memory quantity. The data are data determined in a classified manner individually for each of conditions of use that are defined in such a manner as to include an open circuit voltage and a temperature. The electronic control unit is configured to sequentially calculate, with reference to the data, the memory quantity within a time when classification of the conditions of use does not change. The memory quantity is a quantity indicating an amount of change in voltage resulting from a memory effect. The electronic control unit is configured to estimate a current memory quantity of the nickel hydride battery by integrating the calculated memory quantity.

The present invention provides a battery electrode comprising an active battery material enclosed in the pores of a conductive nanoporous scaffold. The pores in the scaffold constrain the dimensions for the active battery material and inhibit sintering, which results in better cycling stability, longer battery lifetime, and greater power through less agglomeration. Additionally, the scaffold forms electrically conducting pathways to the active battery nanoparticles that are dispersed. In some variations, a battery electrode of the invention includes an electrically conductive scaffold material with pores having at least one length dimension selected from about 0.5 nm to about 100 nm, and an oxide material contained within the pores, wherein the oxide material is electrochemically active.

A nickel hydroxide includes stacked nickel hydroxide layers. Each of the nickel hydroxide layers includes Ni.sup.2+ and OH.sup.−. At least one of the nickel hydroxide layers further includes a type of polyatomic anions. The polyatomic anions include a type of anions that are not SO.sub.4.sup.2− or CO.sub.3.sup.2−.

A nickel hydroxide includes stacked nickel hydroxide layers. Each of the nickel hydroxide layers includes Ni.sup.2+ and OH.sup.−. At least one of the nickel hydroxide layers further includes a type of polyatomic anions. The polyatomic anions include a type of anions that are not SO.sub.4.sup.2− or CO.sub.3.sup.2−.

An electrode for a battery includes an iron-containing substrate and a cobalt ferrite layer disposed over the iron-containing substrate. Advantageously, the cobalt ferrite layer inhibits corrosion of the iron-containing substrate. A nickel hydroxide layer is disposed over the cobalt ferrite layer. A battery incorporating the electrode is also provided.

An electrode for a battery includes an iron-containing substrate and a cobalt ferrite layer disposed over the iron-containing substrate. Advantageously, the cobalt ferrite layer inhibits corrosion of the iron-containing substrate. A nickel hydroxide layer is disposed over the cobalt ferrite layer. A battery incorporating the electrode is also provided.