An AC (Alternating Current) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, fans and electric lamps into a wall socket. 

Aluminium alloys are when aluminum (AI) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories heat-treatable and non-heat-treatable. In lithium-ion batteries, where thin-walled formation is required, aluminum alloys are used.

Ammonia is a compound of nitrogen and hydrogen with the formula NH3. It has nine times the energy density of Li-ion batteries, and three times that of compressed hydrogen, creating potential as a carbon-free energy carrier and less volatile fluid than compressed or liquid hydrogen.

Amorphous graphite is found as extremely small, crystal-like particles in beds of mesomorphic rocks like coal, slate and shale, and its carbon content depends on that of its parent material. There are three main types of graphite: Flake, vein, and amorphous. Graphite is a key component in the lithium-ion host structure for the negative electrode. Graphite is used in the majority of commercial lithium-ion batteries, despite extensive research to find alternatives with enhanced power and/or energy density, while maintaining the excellent cycling stability.

The ampere, or 'amp' for short, measures electric current, which is a flow of electrons along a wire or ions in an electrolyte, as in batteries.

An anode is the positive electrode through which the conventional current enters into a polarised electrical device. This contrasts with a cathode, the negative electrode through which conventional current leaves an electrical device. A common mnemonic is ACID, for "anode current into device".