Ion-Transport-Rectifying Layer Enables Li-Metal Batteries with High Energy Density

The lithium-metal battery (LMB) holds great promise for various applications for which high energy density is required; the adoption of LMB, however, is limited by poor performance of the lithium-metal anode (LMA), which is intrinsically associated with the unregulated ion transport and reaction. By coating an ion-transport rectifier on the LMA, which was synthesized from a metal-organic framework with high lithium-ion transference number and conductivity, we report here the fabrication of an LMB with a thin Li anode (≤50 μm), a thick LiCoO2 cathode (4 mAh cm−2), and lean electrolyte condition. Such an LMB can potentially deliver high gravimetric and volumetric energy density exceeding that of state-of-the-art lithium-ion batteries. This work offers a new strategy to regulate the ion transport and reaction at electrode-electrolyte interphase, facilitating the development of practical LMB for a broad range of applications.