Planar Zn-Ion\nMicrocapacitors with High-Capacity Activated\nCarbon Anode and VO<sub>2</sub> (B) Cathode

The downsizing of\nmicroscale energy storage devices plays\na crucial\nrole in powering modern emerging devices. Therefore, the scientific\nfocus on developing high-performance microdevices, balancing energy\ndensity and power density, becomes essential. In this context, we\nexplore an advanced Microplotter technique to fabricate hybrid planar\nZn-ion microcapacitors (ZIMCs) that exhibit dual charge storage characteristics,\nwith an electrical double layer capacitor type activated carbon anode\nand a battery type VO<sub>2</sub> (B) cathode, aiming to achieve energy\ndensity surpassing supercapacitors and power density exceeding batteries.\nEffective loading of VO<sub>2</sub> (B) cathode electrode materials\ncombined with activated carbon anode onto confined planar microelectrodes\nnot only provides reversible Zn<sup>2+</sup> storage performance but\nalso mitigates dendrite formation. This not only results in superior\ncharge storage performance, including areal energies of 2.34 μWh/cm<sup>2</sup> (at 74.76 μW/cm<sup>2</sup>) and 0.94 μWh/cm<sup>2</sup> (at 753.12 μW/cm<sup>2</sup>), exceeding performance\nof zinc nanoparticle anode and activated carbon cathode based ZIMCs,\nbut also ensures stable capacity retention of 87% even after 1000\ncycles and free from any unwanted dendrites. Consequently, this approach\nis directed toward the development of high-performance ZIMCs by exploring\nhigh-capacity materials for efficient utilization on microelectrodes\nand achieving maximum possible capacities within the constraints of\nthe limited device footprint.