Recently the Researchers in Canada had developed a biodegradable battery which is made from tree pulp literal wood that fully dissolves in soil within 60 days and leaves behind zero toxic waste. No lithium, no heavy metals, just sustainable innovation.
This is still in the research phase and right now it only powers small things like sensors or LEDs but this is a huge step forward. By this disposable electronics the planet will not pollute. The power output is low for now, but the idea is big a future with eco friendly, soil safe batteries made from natural materials.
