Metal nanoclusters (NCs) consist of tens to hundreds of metal atoms with a diameter of <2 nm, and have attracted significant attention due to their unique molecule-like properties, such as well-defined molecular structures, explicit HOMO–LUMO transitions, quantized charge and strong luminescence emission. Various robust synthetic protocols have been successfully applied to the preparation of metal NCs. Among metal NCs, Au NCs stay at the frontline of this research, and more structural characteristics, particular optical, catalytic and electronic properties, and related technical applications of Au NCs have been discovered in recent years. By taking guidelines from Au NC research, Ag NCs have recently received increasing attention. In this review article, we first survey recent advances in developing efficient synthetic methods for Ag NCs, highlighting the underlying physical and chemical properties that make the delicate control of their sizes and surfaces possible. In the following section, we discuss recent advances in the structural determination of Ag NCs, such as Ag₂₅(2,4-DMBT)₁₈ (2,4-DMBT: 2,4-dimethylbenzenethiolate), Ag₂₉(1,3-BDT)₁₂ (1,3-BDT: 1,3-benzenedithiolate), and Ag₄₄(SR)₃₀ (R = PhCO₂H₂, PhF, PhF₂ or PhCF₃). Structural determination will help to gain deep insight into the structure–property relationships at the molecular level. In the last part, we highlight some examples of Ag NCs to demonstrate their photoluminescence properties, which offer potential applications as photodetectors and in sensing and bio-imaging. We give a brief outlook on the future development of Ag NCs from the viewpoint of synthesis and applications.

Ammonium ions (NH₄⁺) are emerging non‐metallic charge carriers for advanced electrochemical energy storage devices, due to their low cost, elemental abundance, and environmental benignity. However, finding suitable electrode materials to achieve rapid diffusion kinetics for NH₄⁺ storage remains a great challenge. Herein, a 2D conjugated metal–organic framework (2D c‐MOF) for immobilizing iodine, as a high‐performance cathode material for NH₄⁺ hybrid supercapacitors, is reported. Cu‐HHB (HHB = hexahydroxybenzene) MOF embedded with iodine (Cu‐HHB/I₂) features excellent electrical conductivity, highly porous structure, and rich accessible active sites of copper‐bis(dihydroxy) (Cu─O₄) and iodide species, resulting in a remarkable areal capacitance of 111.7 mF cm⁻² at 0.4 mA cm⁻². Experimental results and theoretical calculations indicate that the Cu─O₄ species in Cu‐HHB play a critical role in binding polyiodide and suppressing its dissolution, as well as contributing to a large pseudocapacitance with adsorbed iodide. In combination with a porous MXene anode, the full NH₄⁺ hybrid supercapacitors deliver an excellent energy density of 31.5 mWh cm⁻² and long‐term cycling stability with 89.5% capacitance retention after 10 000 cycles, superior to those of the state‐of‐the‐art NH₄⁺ hybrid supercapacitors. This study sheds light on the material design for NH₄⁺ storage, enabling the development of novel high‐performance energy storage devices.