Abstract Zinc–air batteries (ZABs) are regarded as promising options for sustainable energy storage due to their high specific energy density, cost-effectiveness, and environmental friendliness. However, their scalability is rendered challenging because of high overpotential, slow kinetics in the bifunctional oxygen evolution reaction/oxygen reduction reaction, and instability in alkaline environments. Herein, we report the development of a highly active bifunctional oxygen catalyst, denoted as TON@NC (trimetallic oxide needles on nitrogen-doped carbon), which consists of Ni-Co-Fe oxide nanoneedles uniformly anchored on a nitrogen-doped carbon network. The synthesis of TON@NC is implemented by a hydrothermal process that creates hydroxide, followed by thermal heating using microwaves. The optimized TON@NC catalyst retains its desirable structural porosity and exhibits exceptional bifunctional oxygen catalytic performance owing to well-designed oxygen vacancies and suitable crystallite sizes. TON@NC demonstrates enhanced performance in oxygen catalytic reactions, with a half-wave potential of 0.78 V and an active potential of 1.49 V in alkaline environments, outperforming carbon-based precious metal catalysts. Furthermore, ZABs employing TON@NC as the air cathode show remarkable cycling stability over 300 h and an outstanding output power density of 100.5 mW cm −2 . This facile and adaptable synthetic strategy can accelerate the development of porous hybrids composed of precisely engineered nitrogen-doped carbon backbones combined with advanced multi-metallic catalysts for energy storage applications. Microwave-assisted reconstruction strategy is devised to fabricate a highly active bifunctional oxygen catalyst, named as TON@NC, in which Ni-Co-Fe trimetallic oxide needles are anchored on nitrogen-doped carbon network structures. TON@NC demonstrates highly enhanced oxygen catalytic reactions, with a half-wave potential of 0.78 V and an active potential of 1.49 V in alkaline environments, while ZABs employing TON@NC as the air cathode show remarkable cycling stability over 300 h and an outstanding output power density of 100.5 mW cm −2 . Graphical Abstract

The environmental burden of vapor compression refrigeration has driven interest in alternatives. Caloric refrigeration cycles offer a path forward, but most rely on solid-state materials with limited temperature lift, low performance, and poor fluidity, which hinder scalability. We introduce a liquid-phase dipolarcaloric refrigeration cycle utilizing endothermic dissolution of nitrate-based salts regenerated through electrodialysis. This cycle achieves large adiabatic temperature changes and high coefficients of performance. We identified effective saltwater pairs and validated the cycle experimentally, supported by thermodynamic modeling. Among these pairs, ammonium nitrate is suited for refrigeration, and potassium nitrate is appropriate for air conditioning. The system uses abundant, low-cost materials, and its fluidic nature ensures efficient heat transfer and scalability. This work establishes dipolarcaloric cooling as a viable alternative for environmentally responsible refrigeration.