Tree-huggers rejoice! Today Sony announced the realization of a mercury-free alkaline button battery (LR), and plans to commercialize six models of environmentally conscious batteries. 

With conventional alkaline button batteries mercury is added to the anode material to prevent the occurrence of hydrogen gas. As the cathode material used in these batteries was known to have a low rate of hydrogen gas absorption made the creation of a totally mercury-free alkaline button battery a significant technological challenge. The mercury-free alkaline button battery announced today incorporates proprietary Sony technology that mixes absorbent raw material into the cathode for the first time. By combining this with existing technology that prevents hydrogen gas occurrence on the anode (which Sony originally adopted in its mercury-free silver oxide (SR) button batteries), Sony has succeeded in eliminating the use of mercury.