When electronic products need power, there are two basic choices: battery and collector. Batteries store energy internally, but are therefore heavy and supply is limited. Collectors such as solar panels collect energy from the surrounding environment. This solves some shortcomings of batteries, but introduces new batteries because they can only work under specific conditions and can not quickly convert energy into useful energy.
A new study by the school of engineering and Applied Sciences of the University of Pennsylvania, in the form of “metal air cleaner”, fills the gap between these two basic technologies for the first time and meets these two needs at the same time.
The metal air cleaner works like a battery. It provides energy by repeatedly breaking and forming a series of chemical bonds. But its working principle is the same as that of the collector, because its energy is provided by the energy in the surrounding environment: specifically, the chemical bonds in the metal and air surround the metal air cleaner.
As a result, the energy density of this energy source is 10 times that of the best energy collector and 13 times that of lithium-ion battery.
In the long run, this type of energy may become the basis of a new paradigm of robotics. In robotics, machines maintain their own energy supply by looking for and “eating” metals. Just as humans eat food, they break down the chemical bonds of metals to obtain energy.
In the short term, this technology has provided power for the two subsidiaries. The winners of the Y prize of the year at the University of Pennsylvania plan to use metal air cleaners to provide low-cost lighting for families without electricity in developing countries, and install durable sensors for containers to warn against theft, damage and even human trafficking.
James Pikul, assistant professor of the Department of mechanical engineering and applied mechanics, together with laboratory members Min Wang and unnati Joshi, published a study in ACS energy letters to demonstrate this new energy.
The motivation for the development of metal air cleaners (MAS) stems from the fact that the technologies that make up the robot brain and the technologies that drive them are fundamentally mismatched in miniaturization.
As the size of a single transistor shrinks, the chip provides greater computing power in a smaller, lighter package. But the battery does not benefit in the same way when it becomes smaller; The density of chemical bonds in the material is fixed, so a smaller battery must mean that fewer chemical bonds will break.
“This inverse relationship between computing performance and energy storage makes it difficult for small devices and robots to run for a long time,” Pikul said. “There are robots the size of insects, but they can only work for a minute, and then the battery runs out.”
To make matters worse, adding a larger battery does not make the robot last longer; The increased mass requires more energy to move, offsetting the additional energy provided by the larger battery. The only way to break this frustrating inverse relationship is to look for chemical bonds, not to pack them together.
“Collectors, like those that collect solar, thermal or vibration energy, are getting better and better,” Pikul said. “They are usually used to power sensors and electronic devices without networking, where you may not be able to change the battery.” the problem is that their power density is very low, which means they can’t absorb energy from the environment as quickly as batteries. “
“The power density of our MAS is ten times that of the best collector, so that we can compete with the battery,” he said. “It uses battery chemicals, but there is no corresponding weight, because it extracts chemicals from the environment.”
Pikul said: “in the near future, we will see that our MAS will promote the development of animal networking technology, as proposed by metal light and m-squared.” “but what really attracts us and the motivation behind this work is how it changes the way we design robot people.”
Most of Pikul’s other research involves improving technology by obtaining clues from nature. For example, the high-strength and low-density “metal wood” in his laboratory is inspired by the cell structure of trees. His research on a robotic lionfish includes giving it a liquid battery circulation system, which also drives its fins pneumatically.
The researchers believe that their MAS uses a more basic biological concept: food.
“As robots become smarter and more capable, we are no longer limited to plugging them into the wall. They can now find energy themselves, just like humans,” Pikul said. “One day, a robot that needs to charge the battery will only need to find some aluminum and ‘eat’ with MAS, which will give it enough energy to work until its next meal.”
Responsible editor; zl