| 摘要 |
772,038. Batteries. UNION CARBIDE & CARBON CORPORATION. April 22, 1955 [April 30, 1954; April 30, 1954; April 30, 1954], No. 11628/55. Class 53. In order to fix the initial voltage of a primary cell having a consumable metal anode having an electrical potential greater than zinc, particularly magnesium, and to maintain a relatively high voltage level during the final portion of its service, an oxidic depolarizer is used having a surface coating of a lower oxide of the depolarizer. With a manganese dioxide as a depolarizer, the lower oxide at its surface is manganic oxide. One method of obtaining Mn 2 0 3 comprises heating the one of Mn0 2 in a reducing gas, e.g. CH 4 , CO 2 , H or a mixture thereof. The resulting coated ore is then stabilized by the addition of an agent to adjust the pH thereof to obtain the desired initial voltage of the cell. Fig. 1 shows a carbon-magnesium cell having a magnesium bromide electrolyte. The cathode 14 is formed of a carbon rod with a depolarizer mix reduced and stabilized as stated above. Another method of forming the coating of Mn 2 0 3 is to mix the Mn0 2 with a reducing agent, e.g. oxalic acid, formic acid, hydrogen peroxide, or manganous oxide, the pH of the mixture is then adjusted. The pH control may be effected by the use of MgO, NH 4 0H, MgOH or MnO. Another method of forming the lower oxide coating comprises forming a mixture of the oxidic depolarizer ore, e.g. MnO 2 and a water-soluble salt of a polyvalent metal, e.g. Mn, Sr, Fe or Pb. If the anode is aluminium instead of magnesium, the oxidic depolarizer may consist of MnO 2 mixed with manganous phosphate or manganous acetate. In cells having zinc anode, the oxidic depolarizer consists of Mn0 2 mixed with MnCl 2 . |
