Abstract: Provided are a cathode active material, a cathode comprising same, and a secondary battery. The cathode active material contains crystal water and a manganese-based metal oxide and has a first crystal phase having a two-dimensional crystal structure and a second crystal phase having a three-dimensional crystal structure, wherein the three-dimensional crystal structure is formed by the combination of manganese in the manganese-based metal oxide and oxygen in the crystal water.

Abstract: Provided are a cathode active material, a cathode comprising same, and a secondary battery. The cathode active material contains crystal water and a manganese-based metal oxide and has a first crystal phase having a two-dimensional crystal structure and a second crystal phase having a three-dimensional crystal structure, wherein the three-dimensional crystal structure is formed by the combination of manganese in the manganese-based metal oxide and oxygen in the crystal water.

Abstract: The present invention provides an asymmetric hybrid capacitor, in which metal oxide containing lithium and capable of producing lithium ions by an electrochemical reaction and supplying the lithium ions in an electrolyte in the capacitor is used as a positive electrode active material, and metal oxide capable of accepting the lithium ions supplied through the electrolyte is used as a negative electrode active material, such that the lithium ions of the same participate in the electrochemical reactions at both electrodes. As a result, it is possible to minimize reduction in ionic conductivity during charge/discharge, compared with conventional asymmetric hybrid capacitors, in which metal oxide and a carbon material are used as electrode materials, respectively. Moreover, since metal oxide having high specific capacitance is used to form both electrodes, it is possible to maximize energy density and power density.