Biomorphic batteries could mean major increases in run time for small robots

Researchers from the University of Michigan have created a new type battery known as a biomorphic battery that could increase the runtime for small robots by 72x. The so-called biomorphic batteries are a new rechargeable zinc battery technology that integrates into the structure of a robot. The team says that the new battery technology will be particularly important as robots shrink to an ever smaller scale.

Current battery technology is unable to scale to smaller sizes without giving up significant energy storage capability. The researchers say that current stand-alone batteries often occupy 20 percent or more of the available space inside the robot. The batteries also often account for a similar portion of the weight of the robot.

Some researchers have turned to multifunctional structural batteries to free up space and reduce weight, but until now, there were only able to supplement the main battery. The University of Michigan researchers say their improvements on prior versions of structural zinc batteries on ten different measures have improved some of those measures a factor of 100x.

One researcher on the project says that the team estimates robots could have 72 times more power capacity if their exterior was replaced with a zinc battery. The new battery works by passing hydroxide ions between a zinc electrode and the airside through an electrolyte membrane. The membrane is partly composed of a network of aramid nanofibers, which are carbon-based fibers found in Kevlar vests.

The battery also uses a new water-based polymer gel to help shuttle hydroxide ions between the electrodes. Researchers say that the batteries are made with cheap and abundant materials that are largely non-toxic, making it more environmentally friendly than other batteries. Another main benefit is the gel and aramid nanofiber won't catch fire if the battery is damaged. The fibers used in the battery can also be upcycled from retired body armor.