Ultrahigh‐Speed Aqueous Copper Electrodes Stabilized by Phosphorylated Interphase

Abstract

AbstractHigh‐energy metal anodes for large‐scale reversible batteries with inexpensive and nonflammable aqueous electrolytes promise the capability of supporting higher current density, satisfactory lifetime, nontoxicity, and low‐cost commercial manufacturing, yet remain out of reach due to the lack of reliable electrode–electrolyte interphase engineering. Herein, 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 is demonstrated. Impressively, an unprecedented ultrahigh‐speed copper plating/stripping capability is achieved at 100 mA cm−2 for over 12 000 cycles, corresponding to an accumulative areal capacity up to tens of times higher than previously reported CMEs. The use of solid‐electrolyte interface‐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 homogenize copper‐ion deposition and suppress nucleation overpotential, enabling dendrite‐free CMEs with sustainability and ability to tolerate unusual‐high power densities. The findings represent an elegant forerunner toward the promising goal of metal electrode applications.