Nanofluid channels mitigated Zn2+ concentration polarization prolonged over 30 times lifespan for reversible zinc anodes

Abstract

Despite interfacial engineering protects zinc anode from electrolyte corrosion, the suppressed kinetics process on the anode surface/interface circumscribes their cyclic stability, especially dendritic growth induced by ion concentration gradients. Here, the zinophilic nanofluid channels (ZNC) protective layer on zinc surface are designed for the rapid Zn²⁺ transport kinetic in the reversible cycling process. The ZNC demonstrates high separation pressure between ions and the channel surface due to the capillary effect, allowing Zn²⁺ to quickly migrate along the channel wall (Zn²⁺ transference numbers up to 0.72). Therefore, the unique channel modules alleviate concentration polarization from rapid Zn²⁺ consumption and maintain uniform deposition of Zn ions. Consequently, The ZNC protective layer anode exhibits significantly improved cycle life by >30 times (over 4000 h at 1 mA cm⁻²) that of bare Zn. The full battery exhibits stable cycling performance with excellent capacity retention (∼100 %) after 5000 cycles. Our work provides innovative insights into the role of nanofluids in improving the stability of zinc anodes, offering enlightening perspectives for long-cycle life zinc-based batteries.