Goli Nagaraju

Printed zinc‐ion batteries (ZnIBs) hold significant promise for micro‐energy storage systems, particularly for powering the Internet of Things (IoT). However, their practical viability is limited by short shelf‐life and poor cycling stability, arising from interfacial degradation, dendrite formation, parasitic side reactions on the Zn anode, and dissolution of cathode material. Addressing these challenges is essential for enabling robust and long‐lasting ZnIBs for energy‐autonomous devices. Here, we report a durable, fully printed Zn‐ion microbattery based on aqueous‐ink‐manufactured microelectrodes, featuring graphene platelets decorated micron‐sized zinc powder (Gr‐µZn) anode and a nitrogen‐doped carbon@manganese oxide (MnO@NC) composite cathode. The printed Gr‐µZn architecture ensures adequate electrical conductivity (2.6 Ω), uniform Zn deposition with low overpotentials (∼50 mV at 1 mA/cm ² after 500 h), good structural integrity and stable operation with low polarization. Furthermore, the fully printed ZnIB exhibits an areal capacity of 1.5 mAh/cm ² (99.8 mAh/g) and an energy density of 2 mWh/cm ² , along with an extended shelf‐life, which are competitive. To demonstrate practical feasibility, we powered a wearable heart‐rate sensor using a printed ZnIBs, which delivered a stable output voltage with ∼70 h of continuous operation. Our work demonstrates a scalable and sustainable platform for high‐performance printed ZnIBs, advancing their integration into self‐powered health monitoring devices.

The rapid accumulation of food waste has emerged as a pressing environmental challenge, motivating the development of sustainable strategies for waste valorization. Developing sustainable routes to transform discarded food-waste into...

IrO₂ is one of the most widely investigated electrocatalysts for oxygen evolution reaction in an acidic environment. Increasing the mass activity is an effective way of decreasing the loading of Ir, to ultimately reduce costs. Here, we demonstrate the crystal-phase engineering of two different potassium iridate polymorphs obtained by designing a selective solid-state synthesis of either one-dimensional K_0.25IrO₂ nanowires with a hollandite crystal structure or two-dimensional KIrO₂ hexagonal platelets. Both structures present increased specific and mass electrocatalytic activities for the water oxidation reaction in acidic media compared to commercial rutile IrO₂ of up to 40%, with the 1D nanowires outperforming the 2D platelets. XANES, extended X-ray absorption fine structure, and X-ray diffraction investigations prove the structural stability of these two different allotropes of KxIrO₂ compounds upon electrocatalytic testing. These low-dimensional nanostructured 1D and 2D KxIrO₂ compounds with superior mass activity to commercial IrO₂ can pave the way toward the design of new electrocatalyst architectures with reduced Ir loading content for proton exchange membrane water electrolyzer (PEMWE) anodes.

Aqueous zinc ion batteries (ZIBs) are attracting increasing attention due to their low cost, earth abundance, and safety. So far, they have been regarded as a promising battery system for large scale grid applications, while here, we demonstrate prospects of their use to power portable devices. We report the fabrication of a rechargeable ZIB with interdigitated geometry capable of powering a commercial sensor for days. A full battery was assembled using aqueous and scalable formulations with a printed anode based on zinc powder and carbon black, a printed colloidal electrolyte, and a printed MnO₂ cathode. The anode withstands more than 500 h of galvanostatic plating/stripping with a low overpotential of ∼32.2 mV, and the ZIB displays a capacity of ∼1.3 mAh/cm² (∼129 mAh/g) and retains ∼66% of its capacity after 100 cycles. Finally, we show how this battery can power a Bluetooth proximity sensor, providing a voltage of 3.2 V for more than 3 days of continuous operation.

Na-ion intercalated MnO ₂ -based bundled fiber electrodes are designed for aqueous Na-ion energy storage with high energy density and power densities.

Combining energy harvesting with energy storage systems in a single device could offer great advantages for continuous power supply in both indoor and outdoor electric applications. In this work, we demonstrate a photochargeable sodium-ion battery (PSIB) based on a photoactive cathode of two-dimensional crystals of MoSe₂. This photocathode enables spontaneous photodriven charging of a sodium-ion battery cathode under illumination and an increase in the reversible capacity to 29% at 600 mA g^-1 compared to that under dark conditions during galvanostatic cycling. Exposure of MoSe₂ to light drives the Na⁺ extraction, prompted by photogenerated holes, and accelerates the charge transfer kinetics with improved ion diffusion, which leads to an increased capacity. Moreover, the PSIB can be charged to 1.68 V under light illumination without applying an external current. Our work paves the way for the development of light-driven rechargeable batteries, which can benefit off-grid technologies such as the Internet of Things.

Aqueous zinc ion batteries (ZIBs) are attracting increasing attention due to their low cost, earth abundance and safety. So far, they have been regarded as a promising battery system for large scale grid applications, and here we demonstrate prospects of their use to power portable devices. We have fabricated fully 3D printed and rechargeable ZIB with interdigitated geometry capable to power a commercial sensor for days. A full battery was assembled using aqueous and scalable formulations with a printed anode based on zinc powder and carbon black, a printed colloidal electrolyte and a printed MnO2 cathode. The anode withstands more than 500h of galvanostatic plating/stripping with a low overpotential of ~32.2 mV and the ZIB displays a capacity of ~1.3 mAh/cm² and a capacity retention of ~66% after 100 cycles. Finally, we show how this battery can power a Bluetooth proximity sensor for more than 3 days of continuous operation

Nanostructuring electrocatalysts based on precious metals can be an effective tool to increase the dispersion and hence increase the mass activity. Here, we demonstrate the crystal phase engineering of two different potassium iridates polymorphs. We develop a selective solid-state synthesis of either a 1-dimensional K0.25IrO2 nanowires with a hollandite crystal structure, or 2-dimensional KIrO2 hexagonal platelets. Both structures present increased specific and mass electrocatalytic activity for water oxidation reaction in acidic media compared to commercial rutile IrO2 of up to 40%, with the 1D nanowires outperforming the 2D platelets. XANES, EXAFS and XRD investigations prove the structural stability of these two different allotropes of K-IrO2 compounds upon electrocatalytic testing. These low dimensional nanostructured 1D and 2D KxIrO2 compounds with superior mass activity to commercial IrO2 can pave the way towards the design of new electrocatalysts architectures with reduced Ir loading content for Proton Exchange Membrane water electrolyser anodes

Durable and dissolution-free 3D printed VS ₂ electrodes for water-in-salt electrolyte Zn-ion batteries were reported.