The attachment strategy based on catecholic chemistry has been arousing renewed interest since the work on polymerized catecholic amine (polydopamine) (Messersmith et al., Science, 2007, 318, 426) was published. Catechols and their derived compounds can self-assemble on various inorganic and organic materials, including noble metals, metals, metal oxides, mica, silica, ceramics and even polymers. It opens a new route to the modification of various substrates and the preparation of functional composite materials by simple chemistry. However, there is still not a full review so far about the attachment chemistry despite the dramatically increasing number of publications. This critical review describes the state-of-the-art research in the area: the design and synthesis of catecholic molecules, their adsorption mechanisms and the stability of assemblies in solution, and their applications etc. Some perspectives on future development are raised (195 references).

Polydopamine (Pdop) nano/microcapsules are readily produced through the oxidative polymerization of dopamine and the spontaneous deposition of Pdop on the template surface, followed by the removal of the template. The Pdop capsules are very robust and stable under different pH. Most importantly, they exhibit outstanding unidirectional permeability to Rh6G: they can uptake Rh6G but cannot release Rh6G in an aqueous buffer solution. In contrast, in ethanol, the trend is reversed: they cannot uptake but rapidly release Rh6G.

Sodium metal batteries hold great promise for energy-dense and low-cost energy storage technology but are severely impeded by catastrophic dendrite issue. State-of-the-art strategies including sodiophilic seeding/hosting interphase design manifest great success on dendrite suppression, while neglecting unavoidable interphase-depleted Na ⁺ before plating, which poses excessive Na use, sacrificed output voltage and ultimately reduced energy density. We here demonstrate that elaborate-designed fluorinated porous framework could simultaneously realize superior sodiophilicity yet negligible interphase-consumed Na ⁺ for dendrite-free and durable Na batteries. As elucidated by physicochemical and theoretical characterizations, well-defined fluorinated edges on porous channels are responsible for both high affinities ensuring uniform deposition and low reactivity rendering superior Na ⁺ utilization for plating. Accordingly, synergistic performance enhancement is achieved with stable 400 cycles and superior plateau to sloping capacity ratio in anode-free batteries. Proof-of-concept pouch cells deliver an energy density of 325 Watt-hours per kilogram and robust 300 cycles under anode-less condition, opening an avenue with great extendibility for the practical deployment of metal batteries.