A group of researchers from the University of Illinois, combining methods of 3D-holographic lithography and conventional two-dimensional photolithography, created a microscopic but highly efficient battery. Miniature dimensions of created battery will allow to integrate it directly into chips of microelectronic devices, making these chips are absolutely independent of external sources of electric energy.
“Our 3D microbattery has exceptional electrical characteristics, and the technology of production of such batteries can be scaled to any size, so thanks to this, the batteries can be used in the widest range of areas,” – says Paul Brown, professor of the University of Illinois.
The researchers used a 3D-holographic lithography for creation of complex internal structure of the electrodes and with the help of two-dimensional photolithography was given the necessary external form. In this work, were used all the latest technologies of simulation and manufacturing, the totality of which gave high capacitance and energy storage density.
In the 3D-holographic lithography technology are used a few laser beams that are focused at particular points of the photosensitive material, creating microscopic structures of any complexity in the bulk material.
A large area of the electrode and its porous structure allows the rapid transfer of electric charges by means of electrons and ions. Moreover, carefully designed electrode grates prevent the accumulation of lithium ions near the one of the electrodes, which increases the reliability of its operation, that is, number of charge-discharge cycles in comparison with batteries having conventional graphite electrodes.
Prototypes of new 3D microbatteries which thickness is about 10 microns, and the area – 4 square millimeters, were capable of delivering 500 mA of current, maintaining conventional Light-emitting diode for 600 seconds of time. And after 200 charge-discharge cycles, the total capacity of the battery has decreased by only 12 percent.
“We have developed a method of producing of three-dimensional lithium-ion batteries, which is fully compatible with existing semiconductor technologies of chip manufacturing,” – said Hailong Ning, one of the scientists.