Batteries were constructed from interlaced stacks of tiny electrodes, which conduct electricity, smaller than the width of a human hair The microbatteries can be used in devices too small for older batteries Researchers at Harvard and University of Illinois created electrochemically active ink for their custom 3D printerThe revolutionary technology behind 3D-printed car parts, food and guns can also be used to print batteries smaller than a grain of sand. Scientists have used a 3D printer to make linthium-ion microbatteries that can fit into tiny devices that had previously stumped engineers looking to power them for longer periods. The batteries...