It’s a nuisance when a rechargeable battery in your personal stereo goes flat, but if the battery fails in an implant designed to kick-start your heart, it’s a matter of life and death. Lithium batteries can refuse to recharge if their voltage falls below 2.5 volts, because a salty electrolyte within them begins to eat away copper in the electrodes.
Now Californian company Quallion has discovered a simple trick for avoiding battery failure (WO 03/005465). The company added nickel to the copper and lithium in the battery’s positive electrode, and made the negative electrode from titanium and graphite instead of…
