▎ 摘　　要

NOVELTY - Quaternary oxide (I) is new. USE - (I) are useful for preparing cathode, which is useful in an electrochemical cell and a battery (all claimed). ADVANTAGE - (I) provides: the electrochemical cell that exhibits discharge capacity of 80-120 mAh/g at 0.05° C; a simple energy savvy room temperature method for the preparation of the cathode; easy and inexpensive process for preparing layered manganese-based electrode material; and highly crystalline oxides, capable of accommodating greater number of potassium-ions for intercalation/de-intercalation and exhibits high structural flexibility due to its layered structure and was capable of achieving a high capacity. DETAILED DESCRIPTION - Quaternary oxide of formula (KxNayMn3O7.zH2O) (I) is new. x=greater than 1.2 to less than 1.25; y=greater than 0.24 to less than 0.28; and z=0-1.5. INDEPENDENT CLAIMS are also included for: preparing (I); a cathode comprising (a) (I), (b) a conducting carbon, (c) an additive and (d) a substrate, where the cathode has an active mass loading of 2-10 mg/cm2; preparing the cathode comprising (a) mixing (I), the conducting carbon and the additive in the weight ratio of 75:13:12-85:8:7 in a second solvent to obtain a slurry, (b) coating the slurry on the substrate followed by drying at a temperature of 75-85° C to obtain the cathode, where the cathode has an active mass loading of 2-10 mg/cm2; an electrochemical cell comprising (a) a working electrode comprising the cathode, (b) a reference electrode, (c) a counter electrode and (d) a first electrolyte, where the electrochemical cell exhibits discharge capacity of 80-120 mAh/g at 0.05° C; and a battery comprising (a) the cathode, (b) an anode and (c) a second electrolyte.