Ultrahigh‐Speed Aqueous Copper Electrodes Stabilized by Phosphorylated Interphase

Abstract

High‐energy metal anodes for large‐scale reversible batteries with inexpensive and non‐flammable aqueous electrolytes promise the capability of supporting higher current density, satisfactory lifetime, non‐toxicity, and low‐cost commercial manufacturing, yet remain out of reach due to the lack of reliable electrode‐electrolyte interphase engineering. Herein, we demonstrate in situ formed robust interphase on copper metal electrodes (CMEs) induced by a trace amount of potassium dihydrogen phosphate (0.05 M in 1 M CuSO₄‐H₂O electrolyte) to fulfill all aforementioned requirements. Impressively, an unprecedented ultrahigh‐speed copper plating/stripping capability is achieved at 100 mA cm⁻² for over 12000 cycles, corresponding to an accumulative areal capacity up to tens of times higher than previously reported CMEs. The use of SEI‐protection strategy brings at least an order of magnitude improvement in cycling stability for symmetric cells (Cu||Cu, 2800 h) and full batteries with CMEs using either sulfur cathodes (S||Cu, 1000 cycles without capacity decay) or zinc anodes (Cu||Zn with all‐metal electrodes, discharge voltage ∼1.02 V). The comprehensive analysis reveals that the hydrophilic phosphate‐rich interphase nanostructures homogenized copper‐ion deposition and suppressed nucleation overpotential, enabling dendrite‐free CMEs with sustainability and ability to tolerate unusual‐high power densities. Our findings represent an elegant forerunner toward the promising goal of metal electrode applications.

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