{"id":2619,"date":"2024-08-24T12:45:52","date_gmt":"2024-08-24T12:45:52","guid":{"rendered":"https:\/\/workhouse.sweetdishy.com\/?p=2619"},"modified":"2024-08-24T12:45:53","modified_gmt":"2024-08-24T12:45:53","slug":"nickel-iron-alkaline-cell","status":"publish","type":"post","link":"https:\/\/workhouse.sweetdishy.com\/index.php\/2024\/08\/24\/nickel-iron-alkaline-cell\/","title":{"rendered":"NICKEL\u2013IRON ALKALINE CELL"},"content":{"rendered":"\n

It is also known as Edison cell as it was developed by an American scientist Thomson A Edison in 1909.<\/p>\n\n\n\n

<\/a>4.13.1  Construction<\/h4>\n\n\n\n

It contains two plates, that is, a positive plate (cathode) and a negative plate (anode). The active material of cathode is Ni(OH)4<\/sub> and of anode is iron (Fe) when fully charged. The two plates are immersed in the electrolyte, a solution of potassium hydroxide (KOH). The specific gravity of the electrolyte is 1.2. In this case, the container is made of nickel-plated iron to which negative plates are connected. This cell is quit compact as small quantity of electrolyte is used.<\/p>\n\n\n\n

4.13.2  Working<\/h4>\n\n\n\n

When the cell is fully charged, its positive plate is of Ni(OH)4<\/sub> and its negative plate is of iron (Fe). The electrolyte is potassium hydroxide (KOH) of specific gravity 1.2. When dissolved in water, the KOH is dissociated into potassium (K+<\/sup>) and hydroxyl (OH\u2212<\/sup>) ions.<\/p>\n\n\n\n

4.13.3  Discharging<\/h4>\n\n\n\n

When a load (resistor) is connected across the terminals of the cell, the hydroxyl ions go to anode and potassium ions go to cathode. The following chemical action takes places during discharging:<\/p>\n\n\n\n

At anode:     Fe + 2OH \u2192 Fe(OH)2<\/sub><\/p>\n\n\n\n

At cathode   Ni(OH)4<\/sub> + 2K \u2192 2KOH + Ni(OH)2<\/sub><\/p>\n\n\n\n

Therefore, cathode is converted from Ni(OH)4<\/sub> to Ni(OH)2<\/sub> and anode is converted from iron (Fe) to iron hydroxide Fe (OH)2<\/sub>. However, the strength of the electrolyte remains the same.<\/p>\n\n\n\n

4.13.4  Recharging<\/h4>\n\n\n\n

When the cell is put on charging, the hydroxyl (OH\u2212<\/sup>) ions move towards cathode and potassium (K+<\/sup>) ions move towards anode. The following chemical actions take place during recharging:<\/p>\n\n\n\n

At anode:      Ni(OH)2<\/sub> + 2OH \u2192 Ni(OH)4<\/sub><\/p>\n\n\n\n

At cathode:   Fe(OH)2<\/sub> + 2K \u2192 Fe + 2KOH<\/p>\n\n\n\n

Therefore, both the electrodes regain their original chemical composition without changing the strength of the electrolyte.<\/p>\n\n\n\n

4.13.5  Electrical Characteristics<\/h4>\n\n\n\n
    \n
  1. The emf of a fully charged cell is 1.4 V which decreases to 1.3 V rapidly. However, the average emf of the cell is 1.2 V which decreases to 1.0 V when fully discharged.<\/li>\n\n\n\n
  2. The internal resistance of this cell is quite high nearly 5 times to that of a lead\u2013acid cell.<\/li>\n\n\n\n
  3. The A-H efficiency of this cell is nearly 80%, whereas the W-H efficiency is 60%.<\/li>\n<\/ol>\n\n\n\n

    4.13.6  Advantages<\/h4>\n\n\n\n

    It has the following advantages in comparison to that of a lead\u2013acid cell:<\/p>\n\n\n\n

      \n
    1. Longer life\u2014about 5 year<\/li>\n\n\n\n
    2. Its electrolyte (KOH) is not harmful if spilled away.<\/li>\n\n\n\n
    3. <\/a>The specific gravity of its electrolyte does not change when discharged; therefore, it can be left in a fully discharged condition for a considerable period of time without damage.<\/li>\n\n\n\n
    4. Lower weight\u2014nearly half to that of lead\u2013acid cell.<\/li>\n\n\n\n
    5. It can be discharged and recharged at higher rate for longer period without damage.<\/li>\n\n\n\n
    6. It can withstand higher temperature.<\/li>\n\n\n\n
    7. It is more rugged and can withstand more mechanical and electrical stresses.<\/li>\n<\/ol>\n\n\n\n

      4.13.7  Disadvantages<\/h4>\n\n\n\n
        \n
      1. Higher cost\u2014nearly double.<\/li>\n\n\n\n
      2. As the emf developed per cell is less (only 1.2 V), more number of cells are required for a particular voltage.<\/li>\n\n\n\n
      3. Higher internal resistance\u2014nearly 5 times. Therefore, it cannot provide large current and is unsuitable for automobile starting.<\/li>\n\n\n\n
      4. Lower efficiency.<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

        It is also known as Edison cell as it was developed by an American scientist Thomson A Edison in 1909. 4.13.1  Construction It contains two plates, that is, a positive plate (cathode) and a negative plate (anode). The active material of cathode is Ni(OH)4 and of anode is iron (Fe) when fully charged. The two plates are […]<\/p>\n","protected":false},"author":1,"featured_media":2597,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[406],"tags":[],"class_list":["post-2619","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-batteries-basic-for-electrical-eng"],"jetpack_featured_media_url":"https:\/\/workhouse.sweetdishy.com\/wp-content\/uploads\/2024\/08\/battery-2.png","_links":{"self":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/2619","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/comments?post=2619"}],"version-history":[{"count":1,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/2619\/revisions"}],"predecessor-version":[{"id":2620,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/2619\/revisions\/2620"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media\/2597"}],"wp:attachment":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media?parent=2619"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/categories?post=2619"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/tags?post=2619"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}