In this paper, we report a facile large-scale synthesis of the “smallest” (i.e., unimolecular) polymeric Janus nanoparticles from a polystyrene-b-poly(2-vinylpyridine)-b-poly(ethylene oxide) (PS-b-P2VP-b-PEO or SVEO) triblock copolymer by efficient intramolecular cross-linking of the middle P2VP block using 1,4-dibromobutane (DBB) in a common solvent, N,N-dimethylformamide (DMF), due to effective steric shielding of PS and PEO end blocks. Size-exclusion chromatography results indicated that intramolecular cross-linking of the middle P2VP block could take place when the polymer concentration was relatively high (20 mg/mL) and/or the DBB-to-2VP molar ratio was high. Dynamic and static light scattering experiments confirmed the unimolecular form for these polymeric Janus nanoparticles. After intramolecular cross-linking, DMF changed from a good to a slightly poor solvent, as evidenced by the negative apparent second Virial coefficient for the unimolecular Janus nanoparticles determined by SLS. As a result, concentration-dependent self-assembly in DMF was observed. At low concentrations (<2.0 mg/mL), the majority of the unimolecular polymeric Janus nanoparticles existed in the unimolecular form. When the concentration gradually increased, the unimolecular polymeric Janus nanoparticles started to aggregate into supermicelles (R
h = 50−100 nm), where PS formed the supercore and PEO formed the corona with cross-linked P2VP nanoparticles in between. The amphiphilic nature of these unimolecular Janus nanoparticles will enable us to study programmable and hierarchical self-assembly of asymmetrically modified polymeric nanoparticles in various solvents.
Aqueous zinc ion batteries (ZIBs) have been extensively investigated as a next‐generation energy storage system due to their high safety and low cost. However, the critical issues of irregular dendrite growth and intricate side reactions severely restrict the further industrialization of ZIBs. Here, a strategy to fabricate a semi‐immobilized ionic liquid interface layer is proposed to protect the Zn anode over a wide temperature range from −35 to 60 °C. The immobilized SiO2@cation can form high conjugate racks that can regulate the Zn2+ concentration gradient and self‐polarizing electric field to guarantee uniform nucleation and planar deposition; the free anions of the ILs can weaken the hydrogen bonds of the water to promote rapid Zn2+ desolvation and accelerate ion‐transport kinetics simultaneously. Because of these unique advantages, the cycling performance of the symmetric Zn batteries is greatly enhanced, evidenced by a cycling life of 1800 h at 20 mA cm−2, and a cycle lifespan of 2000 h under a wide temperature window from −35 to 60 °C. The efficiency of this semi‐immobilizing strategy is well demonstrated in various full cells including pouch cells, showing high performance at large current (20 A g−1) and wide temperatures with extra‐long cycles up to 80 000 cycles.
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