High-Performance Zn-Ion Microbatteries by Subtractive Manufacturing

Microbatteries are indispensable to power emerging miniaturized electronics for medical, environmental, or stealth applications. However, they are usually fabricated by additive printing processes, limiting their sizes and energy densities. Here, we develop a subtractive manufacturing process by slicing assembled thin-film zinc-ion batteries into microcells in batches using optimized preintercalated MnO2 (K0.27MnO2·0.54H2O, KMO) as cathodes. The composite cathode consisting of KMO and reduced graphene oxide (rGO) delivers a high specific capacity of 323.4 mAh g–1 at 0.1 A g–1 with no capacity loss after 750 cycles at 1 A g–1. Such a high performance renders Zn//KMO/rGO solid-state microbatteries with areal energy densities of 0.244 mWh cm–2, which are comparable to those of the state of the art. This microbattery, with an area of 4 × 4 mm2 and a thickness of 0.56 mm, can be modularly arranged on a chip for a stretchable energy-supply circuit, which can be closely attached to human skin.