A Sub‐Square‐Millimeter Microbattery with Milliampere‐Hour‐Level Footprint Capacity

Abstract

As substantial progress has been made to miniaturize intelligent microsystems to the sub‐square‐millimeter scale, there is a desperate need to move beyond existing microbattery technologies to offer adequate energy at the same footprint. A micro‐origami technology able to wind up a flat layer stack into a Swiss roll presents a promising approach in this regard because it mimics the most successful way to make energy‐dense full‐sized batteries. Here, an on‐chip Swiss‐roll current collector made via the micro‐origami process is developed and it is infused with a MnO2 slurry comprising a zincophilic binder. The zincophilic binder layer enhances zinc ion transportability and suppresses MnO2 dissolution. The MnO2 Swiss‐roll microelectrode is used to create an on‐chip microbattery with a small electrode footprint area of 0.75 mm2, which shows a footprint capacity up to 3.3 mAh cm–2. The microbattery demonstrates a reversible capacity of more than 1 mAh cm–2 for 150 cycles. The battery stability can be improved to over 600 cycles at a 50% depth of discharge. An on‐chip integration of a microsystem with the microbattery is demonstrated. The microbatteries set foot in the untrodden sub‐square‐millimeter area providing adequate energy for ever more miniaturized intelligent microsystems.

Microbatteries with twin-Swiss-rolls redefine performance limits in the sub-square millimeter range

“…a small footprint. [14][15][16][17][18][19] 3D microbatteries often consist of interdigitated electrodes with a large aspect ratio of height to footprint in an attempt to maximize material loading of the electrode. [20][21][22] The energy density of such a 3D microbattery can reach up to 1 mW h cm À2 .…”

“…Engineering 2D active thin-film materials into three-dimensional (3D) structures is an effective way to enhance the energy storage ability of microbatteries while maintaining a small footprint. 14–19 3D microbatteries often consist of interdigitated electrodes with a large aspect ratio of height to footprint in an attempt to maximize material loading of the electrode. 20–22 The energy density of such a 3D microbattery can reach up to 1 mW h cm −2 .…”

High Energy Density Picoliter Zn-Air Batteries for Colloidal Robots and State Machines

“…[13][14][15][16] Sub-square-millimeter batteries were only reported very recently, but they were neither picoliter-sized nor colloidal. [17][18][19] In this work, we photolithographically pattern the highest energy density microbatteries at the picoliter (10 -12 L) scale demonstrated to date, for the purpose of powering robotic devices on the microscale.…”

Programming 3D curved mesosurfaces using microlattice designs

“…Because of the high surface areas, large pore volumes, and excellent mechanical and thermal properties of cellular structures, cellular designs have been exploited in the development of materials and functional systems (9,10). Examples include lattice materials and foams with high specific stiffness, specific strength, and impact resistance (3,(11)(12)(13)(14)(15); porous elec-trodes with small ion diffusion distances and large percentages of active materials for highpower lithium ion batteries (16,17); artificial tissues and organs with hierarchical vascularized networks capable of oxygen and nutrient supply and waste removal (5,6,18); electromagnetic metamaterials capable of blocking, absorbing, enhancing, or bending electromagnetic waves (19); and metal-organic frameworks for watersplitting and oxygen-reduction reactions (20).…”