Electrically active/inert dual-function architecture enabled by screen printing grid-like SiO2 on Cu foil for ultra-long life lithium metal anodes

Three-dimensional (3D) current collectors (CCs) have emerged as an effective strategy to inhibit dendrites and ensure the safety of lithium (Li) metal anodes. However, existing 3D CCs are generally too heavy (typically tens of mg cm⁻²) or too thick (tens to hundreds of micrometers), making large-scale production and further application challenging. Additionally, the use of single-component 3D CCs, whether electrically active or inert, only exhibits limited effects on stabilizing Li anodes. Here, we present a scalable screen-printing technique for the synthesis of ultralight (~0.4 mg cm⁻²) and ultrathin (~0.54 μm) SiO₂ grids on Cu foil to regulate both the vertical electric field and Li-ion concentration by forming an electrically active/inert dual-function architecture. This technology breaks the limitations of traditional 3D CCs in material/fabrication costs, weight, thickness and especially, scalability for large-scale fabrication. By using this dual-function architecture, our Cu@SiO₂-grid CCs (~8.31 mg cm⁻²), which are even lighter than the original Cu-foil CCs (~8.85 mg cm⁻²), realize an ultra-smooth anode surface without Li dendrites, and thus leads to an ultra-long cyclic life of over 1500 h at 1 mA cm⁻². The assembled Li metal batteries demonstrate excellent capacity retention of ~80% over 400 cycles at 1 C and ~ 76% over 250 cycles at 5 C, which highlight the promising 3D CCs for practical applications.