Electrochemical properties of nickel-precipitated pyrite as cathode active material for lithium/pyrite cell

The effects of nickel precipitation and the cut-off voltage on the electrochemical properties of a pyrite cathode were investigated by using an electroless nickel-plating method. After nickel precipitation, some nickel particles that were precipitated on the surface of pyrite accumulated between the pyrite powder particles. In the voltage range of 0.4-3.2 V, a cell with nickel-precipitated pyrite exhibited a rapid decrease in discharge capacity and poor columbic efficiency. On the other hand, in the voltage range of 0.8-2 4 V. the cell showed an improved cycle life property and good coulombic efficiency because irreversible reactions below 0.8 V and sulfur oxidation above 2.4 V were suppressed by controlling the cut-off potential and the internal resistance was decreased by nickel precipitation. (C) 2009 Elsevier B.V. All rights reserved.