Anód

Anód is the electrode at which oxidation occurs in an electrochemical cell. It is the site where electrons are removed from chemical species during the redox process, and these electrons flow through the external circuit to the cathode. The term is used across galvanic (voltaic) cells, electrolytic cells, and related technologies such as fuel cells and electrolysis.

The polarity of the anode depends on the type of cell. In a galvanic (spontaneous) cell, the anode is typically the negative electrode, where oxidation takes place and electrons are released into the circuit. In an electrolytic cell, the anode is the positive electrode, where oxidation also occurs but the external power source drives the reaction, pulling electrons away from the electrode.

Anodes can be made from various materials depending on the chemical environment and the desired reaction. In many electrochemical applications, inert anodes such as graphite or platinum are used to avoid dissolution. Other common inert materials include mixed metal oxide (MMO) coatings on titanium. Consumable or active anodes, which dissolve into the electrolyte to supply metal ions (for example, zinc or copper in electroplating), are used when replenishing ions is desired.

Applications of anodes include metal refining, electroplating, water electrolysis, and fuel cells. In electrolysis, the anode often participates in the oxidation of water or the electrolyte’s anions. In fuel cells, the anode is where fuel oxidation occurs, such as hydrogen oxidation in many designs.

Understanding the anód concept helps explain how different electrochemical devices control reaction pathways, material lifetimes, and product formation through electrode design and operating conditions.