FIBER ELECTRODES FOR LITHIUM SECONDARY BATTERIES, MANUFACTURING METHOD THEREFOR, AND LITHIUM SECONDARY BATTERIES PROVIDED WITH FIBER ELECTRODES

摘要

Provided is a method to inexpensively mass produce fiber positive electrodes for lithium secondary batteries, in which a lithium doped transition metal oxide is used as the main active material, and which have excellent charge/discharge cycle characteristics and enable charge/discharge at high current density. To this end, the method comprises (a) a process to form a transition metal oxide or a coating composed of a transition metal hydroxide in a ring shape on a carbon fiber collector, and (b) a process to heat treat the transition metal oxide or coating composed of a transition metal hydroxide formed in a ring shape on the carbon fiber collector at 100-250°C in a solution that contains lithium ions in a sealed system in the presence of an oxidizing agent or a reducing agent and to obtain a lithium doped transition metal oxide coating on the carbon fiber collector. Also provided are a fiber negative electrode for lithium secondary batteries that has high current density and energy density and excellent charge/discharge cycle characteristics, and the manufacture of which is relatively easy, and a manufacturing method therefor. To this end, the fiber negative electrode for lithium secondary batteries has (c) a carbon fiber collector, (d) an outside layer composed of a composite layer of an Sn oxide and MxOy formed in a ring shape on the carbon fiber collector, and (e) an intermediate layer that is present at the boundary between the carbon fiber collector and the outside layer, is composed of an Sn alloy and has lithium occlusion capability. The manufacturing method for the fiber negative electrode for lithium secondary batteries comprises a process to form on the carbon fiber collector a coating of at least one type of metal selected from a group comprising Fe, Mo, Co, Ni, Cr, Cu, In, Sb and Bi and an Sn coating, or an Sn alloy coating, using electroplating, and then perform heat treatment at 350-650°C in an atmosphere with a trace amount of oxygen. In addition, lithium secondary batteries are provided with a fiber positive electrode and a fiber negative electrode manufactured with the aforementioned methods, and an electrolyte.