Nickel Metal–Organic Decomposition Inks with Tailored Ligand Chemistry and Hybrid Design for Next-Generation Electronics

Nickel-based particle-free metal–organic decomposition (MOD) inks have recently emerged as a compelling alternative to conventional silver and copper systems in printed electronics, offering advantages in cost, corrosion resistance, solution stability, and multifunctional versatility. Despite rapid progress and growing research interest in this field, a dedicated and systematic review encompassing the formulation chemistry, performance enhancement strategies, and application-driven design of Ni-based MOD inks remains conspicuously absent. This work presents a comprehensive and critical review of Ni-based MOD inks. It synthesizes advances across the materials development pipeline─from molecular-scale precursor engineering and ligand field modulation to hybrid/alloy systems (e.g., Ni–Ag, Ni–Cu) and multifunctional device applications. Strategies including mixed-ligand coordination, catalytic heterogeneous nucleation, and ambient-atmosphere sintering are discussed, which enable low-temperature processing (<200 °C), oxidation resistance, and resistivities approaching bulk nickel. Furthermore, the translation of Ni-based MOD inks into functional devices-flexible supercapacitors, printed thermocouples, RFID antennas, and corrosion-resistant sensors-is assessed, demonstrating performance in various applications. To conclude, persistent challenges (e.g., sub-150 °C sintering, substrate adhesion, long-term operational stability) are identified and future research paradigms are proposed, including sustainable ink chemistries, digitally printed multimetal systems, and in situ characterization of decomposition mechanisms. This review not only consolidates current knowledge but also establishes a coherent and forward-looking framework to guide the rational design, scalable fabrication, and application-driven innovation of Ni-based MOD inks for next-generation printed electronics.