UCLA researchers have developed a 3D microbattery design that significantly increases energy storage for small-footprint devices. The battery uses a substrate with an array of vertical posts forming the first electrode, a conformal selectively-cured electrolyte coating, and a second electrode encasing the coated first electrode, yielding higher capacity in millimeter-to-centimeter scale microbatteries.
As microsystems (sensors, implantables, microelectronics) proliferate, there has been an increase in functions like sensing, communication, and computation that need power. However, power sources remain a bottleneck: traditional thin-film microbatteries store insufficient energy per area when scaled down, and often have trade-offs between footprint, energy density, power density, and longevity.
Prior solutions using 2D battery geometries suffer from low active mass and offered limited capacity—even at somewhat larger footprint areas—making them unsuitable for devices that demand both small size and adequate energy.
The new design features three-dimensional first electrode: a dense array of vertically extended posts ("post array") rising from the substrate surface. These posts serve as the active electrode volume allowing much greater electrode surface area and active mass, without expanding the lateral footprint.
A selectively-cured electrolyte coats the posts and substrate conformally, ensuring ion conduction through the complex 3D geometry and close contact.
The second electrode (counter/encasing electrode) substantially envelops the coated electrode to maximize utilization and ensure good ionic and electronic contact.
Increased energy (capacity) per unit area due to higher electrode surface area from vertical post arrays.
Maintained high power density, since thin electroactive layers and conduction paths remain short.
Conformal electrolyte ensures good ionic access throughout the 3D structure.
Potentially comparable cycle life and impedance behavior suited for microsystems.
Powering microscale devices: micro-sensors, micro-implants, MEMS devices, and other embedded systems where footprint is limited.
On-chip power sources for integrated circuits needing standby or intermittent high power bursts.
Internet of Things (IoT) devices located in remote or inaccessible settings where compactness and reliable energy density are required.
Wearables, distributed environmental or structural sensors, and small robotics.
US 10,566,617 B2 — Microbattery Google Patents