Experimental batteries live mostly in sheltered laboratories, communicating to the outside world through rosy reports generated for investors. Some systems show good potential, but many are years away from becoming commercially viable. Others disappear from the scene and die gracefully in the lab without hearing of their passing. Below are the most promising experimental batteries worth mentioning in alphabetical order.
A fuel cell is an electrochemical device that combines hydrogen fuel with oxygen to produce electricity, heat and water. The fuel cell is similar to a battery in that an electrochemical reaction takes place as long as fuel is available. The hydrogen fuel is stored in a pressurized container and oxygen is taken from the air. Because of the absence of a burning process, there are no harmful emissions, and the only by-product is pure water.
The media tells us of wonderful new batteries being developed that promise long runtimes and are paper-thin, durable, cheap and environmental friendly. While these experimental packs may be able to produce a voltage, the downsides are seldom revealed. The typical shortcomings are weak load capabilities and short cycle life. Yes, even a lemon can be made into a battery. Just poke a copper coin and galvanized nail into the innards. The power is low and you need 500 lemons to light a flashlight bulb.
The supercapacitor, also known as ultracapacitor or double-layer capacitor, differs from a regular capacitor in that it has a very high capacitance. A capacitor stores energy by means of a static charge as opposed to an electrochemical reaction. Applying a voltage differential on the positive and negative plates charges the capacitor. This is similar to the buildup of electrical charge when walking on a carpet.