Biomimetic Sandwich-Structured Tubular Ion Pump Arrays for Lithium Metal Batteries

Controlling the rapid, uniform deposition and efficient, stable stripping of Li is crucial for achieving durable high-energy-density Li-metal batteries. Herein, unique biomimetic sandwich-structured tubular ion pump arrays achieved by sandwiching ZnSe nanoparticle tubes between ultrathin N-doped graphene-like layers and vertically aligning on N-doped graphene-Ni foam (NG@ZnSe@NG) are reported, working as a highly efficient and robust Li host for homogeneous and stable Li plating/stripping. After complete lithiation, such a biomimetic tubular ion pump featuring symmetric inner and outer layers with high ion-electron transport rates and a key self-accelerating middle layer is generated, accelerating uniform Li deposition into the interior and efficient stripping of Li from the cavity. Furthermore, the formation process and unique operating mechanism of the ion pump are elucidated in detail across multiple scales using in situ X-ray diffraction (XRD) analyses, in situ transmission electron microscopy (TEM) observations, and theoretical calculations. An ultrahigh Coulombic efficiency of 99.2% over 1100 cycles in asymmetric cells and an ultralong lifespan of 4970 h in symmetric cells are achieved. When assembled with LiFePO4 and O2 cathodes into coin cells, exceptional electrochemical performance is exhibited. Remarkably, under harsh conditions, the NG@ZnSe@NG@Li||NCM83 pouch cell maintains 85.4% capacity retention after 130 cycles at 0.5 C (2.5 mA cm-2), demonstrating excellent stability and reliability in industrial applications.