Selective interfacial adsorption of polyvinylpyrrolidone enables hierarchical microstructural synergy and strength–ductility enhancement in electrodeposited copper foils

Polyvinylpyrrolidone (PVP) selectively chemisorbs on Cu(111) over Cu(220) with ΔE = 3.114 eV. • Single PVP additive (50 mg/L) increases tensile strength by 70.8% (410 MPa) and elongation by 208% (4.0%). • PVP induces hierarchical synergy: grain refinement, dominant (220) texture (Tc = 76%), and more Σ3 twin boundaries. • Adsorbed PVP raises cathodic overpotential and nucleation density by 32.6%, enabling Hall-Petch strengthening. • DFT, XPS, and FT-IR confirm plane-selective chemisorption via C=O→Cu coordination bonding. Enhancing the mechanical properties of electrodeposited copper foil, an essential current collector for negative electrodes in lithium-ion batteries, is crucial for the development of high-energy–density battery. Although chemical additives are widely employed to modulate copper electrodeposition, attaining simultaneous improvements in both strength and ductility remains challenging due to complex additive interactions and incomplete mechanistic insights. This work proposes polyvinylpyrrolidone (PVP) as a versatile single additive for hierarchical microstructural regulation in ultrathin copper foils. With an optimum PVP concentration of 50 mg/L, the produced copper foil demonstrated a tensile strength of 410 MPa (a 70.8% increase) and an elongation of 4.0% (a 208% increase). Microstructural analysis shows that PVP induces a synergistic evolution: refining the grain size, facilitating a dominant (220) texture, and raising the fraction of Σ3 twin boundaries. Combined DFT, XPS, and FT-IR analyses reveal the atomic-scale mechanism: the polar carbonyl groups selectively chemisorb onto Cu(111) via C=O → Cu coordination, with stronger adsorption on Cu(111) than on Cu(220). This suppresses (111) growth, raises overpotential, and enhances nucleation density, resulting in microstructural synergy. These results establish a direct causal chain from selective interfacial adsorption to electrochemical regulation and hierarchical microstructural evolution, ultimately leading to enhanced strength and ductility. Download: Download high-res image (147KB) Download: Download full-size image