An electric cell is a simple device capable of delivering an electric current. One or more electric cells working together to deliver a current constitute a battery. The chemical reaction of an electric cell is categorized as "oxidation-reduction." Electrons are transferred, oxidizing one chemical species through electron removal, while reducing another by adding electrons. The reaction in an electric cell may sometimes be obviously chemical, as for the copper-zinc battery; in other cases, such as the solar cell, it may be less obvious.
Electric cells can find reverse application, as in the process of electroplating, whereby an external voltage is applied that transfers electrons in the reverse direction, resulting in the deposition of metal on substrates. Among the most common deposits are nickel, solder, chromium, copper, silver and gold. Interestingly, solar cells can have their action reversed. Instead of light impinging on their surfaces to produce electricity, current can be introduced that results in light emission, albeit at a different frequency, namely the infrared. This is the principle of the light-emitting diode or LED.
One form of cell undergoing intense investigation is that of the fuel cell. This is especially because of the need for an alternative fuel to replace coal and petroleum. The fuel cell of greatest interest utilizes hydrogen as the fuel. Hydrogen burning in oxygen produces pure water, rather than greenhouse gases and other pollutants. A remaining difficulty is finding the correct electrolyte medium to allow the process to succeed.
There are other, more complex types of fuel cell. Among these are the molten carbonate fuel cell (MCFC), the phosphoric acid fuel cell (PAFC), the proton exchange memory fuel cell (PEM) and solid oxide fuel cell (SOFC). At the current stage of development, all have serious shortcomings. Some require a very high degree of fuel purity, some require expensive platinum catalysis and one requires very high temperatures to function. All use hydrogen gas as the basic fuel.
In 1971, U.S. patent number 3,591,860, was granted for a nuclear industrial device called a gamma electric cell. This invention was designed to produce a high-output voltage directly from nuclear radiation. It is capable of doing so without first passing through a heat cycle. Since it can even produce electricity directly from radioactive isotopes, it is viewed as an alternative safe power source. Unfortunately the invention of the cell phone has been misattributed by some to the holder of the gamma electric cell patent.
