Traditionally, button-type batteries have contained Mercury. I'm pretty sure Mercury is o­ne of the most harmful substances to life, so anything that DOESN'T contain it should be better than something that DOES.

By "button-type" I mean those small batteries...like the o­ne in your wristwatch.

Sony announced o­n the 29th that they will commercialize a new type of oxidized silver button-shaped battery which uses no Mercury. 10 products will be introduced beginning in January of 2005.

Oxidized silver batteries use zinc at the minus pole, oxidized silver at the plus pole, and use an alkaline electrolytic solution. o­n the minus pole, zinc has been traditionally been used - when this is preserved in an alkaline solution, corrosion will occur, creating hydrogen (gas) as a result of the electrolytic breakdown. This gas increasesthe pressure inside of the battery. Because of this, Mercury has traditionally been used in oxidized silver batteries to prevent the corrosion response between it and zinc.

Due to this process, European parliaments and environmental director groups have revised the directives for battery investigations to allow the continued use of Mercury in button-type oxidized silver batteries as an exception to the rules.

The battery oxidized silver battery developed by Sony, however, uses a zinc alloy dust that vastly increases the corrosion resistance of the substance. According to Sony, the alloy is ten times more resistant to corrosion than current zinc. Also, a corrosion supression agent has been used at the minus pole, as well as an anti-corrosive process towards gathering electric charges. These developments have resulted in the commercialization of the world's first Mercury-free oxidized silver battery. Sony has said that the new battery retains the same efficiency as existing batteries, including those that use Mercury.





Inspired by:
http://pc.watch.impress.co.jp/docs/2004/0929/sony.htm

News Release:
http://www.sony.co.jp/SonyInfo/News/Press/200409/04-051/