An electrode is a part of an electrical circuit that makes electrical contact with some nonmetallic part of the circuit. Nonmetal parts include electrolytes, semiconductors or a vacuum. There are a variety of specific electrodes, depending on the particular type of electrode that powers the circuit. Electrodes may also have a more specific name according to their function.
Make electrodes for an electrolytic cell. An electrochemical cell consists of a battery with a wire connected to each terminal. The free ends of the wire are placed in an electrolytic solution. The electrodes are the portions of the wires that are actually in the solution.
Identify the anode and cathode in an electrolytic cell. The electrode connected to the battery’s negative terminal is called the anode and the electrode connected to the battery’s positive terminal is called the cathode.
Build a more efficient electrode by wrapping it around a small cylinder, such as a pen. This will allow an electrode to have a shorter length while maintaining the same surface area. Surface area is one measure of an electrode’s efficiency.
Manufacture electrodes as part of a primary electrochemical cell, such as a non-rechargeable battery. Grind a mixture of manganese dioxide, potassium hydroxide and graphite into a fine powder and press it into tablets. These tablets will then form the cathode of an alkaline battery. Use a gel that consists primarily of zinc powder for the anode of the battery. Separate the cathode and anode with a layer of paper and place them in a metal container. Seal the container to make the battery.
Include electrodes as part of a secondary cell, such as a rechargeable battery. The manufacture of electrodes in secondary cells is similar to that of electrodes in primary cells. However, the electrochemical reaction is reversible in a secondary cell. Therefore, the electrode that is the anode while the battery is charging will become the cathode while the battery is discharging. Similarly, the electrode that is the cathode while the battery is charging will become the anode while the battery is discharging. For example, in an nickel-cadmium battery, the cathode contains cadmium and the anode contains nickel. The battery produces an electrical current when the cadmium flows to the anode and nickel flows to the cathode. Applying an electrical current causes the nickel and cadmium to flow back to their original electrodes, thus recharging the battery.