Beyond Saline Electrolytes: Ultrafast and Selective Ion Transport in Gradient-Ordered Hydrogel Electrolytes Enables High-Rate and Ultra-Stable Energy Storage.

Aqueous ion batteries with traditional hydrogel electrolytes offer high safety, low cost, and simple manufacturing, but are hindered by slow ion transport, limiting fast charging applications. This study develops a gradient-ordered hydrogel (GO-hydrogel) electrolyte via centrifugal sieving. Through centrifugal shear and component design of sol, a gradient structure and a unilateral chain-ordered layer are created. This unique structure enables high-flux, high-rate ion transport and ion selectivity, achieving a conductivity of 53.34 mS cm-1. GO-hydrogel enables aqueous energy systems to outperform liquid electrolytes in rate performance and conventional gels in cycling stability. Sodium-ion batteries withstand 40 A g-1 and retain 92.69% capacity after 20 000 cycles at 5 A g-1, while symmetric supercapacitors show no decay after 10 000 cycles at 1 A g-1. This study is the first to construct gradient ordered ion transport channels via centrifugal shear force, providing a replicable strategy for gel material design in electrochemical energy storage, biomedicine, sensing, and other fields.