Spatially controlled lithium utilization in anode-free all-solid-state batteries via diffusive interface

Abstract

The anode-free solid-state battery represents the perfect balance of safety, cost-effectiveness, and high energy density for future batteries. However, it encounters significant challenges that result in rapid capacity fade in performance. An in situ-formed Li-rich interlayer can establish a diffusive Li-ion dynamic interface where spatially distributed Li⁺ enclosing reduces the rate of void accumulation. Moreover, the uneven Li⁺ flux at the electrolyte interface can be uniform through the Li-rich diffusive interface, leading to uniform deposition of Li⁰ on the current collector. The garnet solid-electrolyte LLZO-Ta (Li_6.75La₃Zr_1.75Ta_0.25O₁₂) has been explored in an all-solid anode-free battery fabrication with a focus on uniform lithium deposition governed by operating conditions through a 500 nm Indium interlayer for enhancing anode-free battery performance. The evolved internal pressure due to the Li–In intermetallic crystal phase change preserves the dimensional stability of the interlayer during Li⁺ diffusion. More Li utilization is achieved through Li–In interlayer without introducing an excess Li source or applying external stack pressure. A Li-rich interphase coupled with cycling protocols can provide more lithium accessibility during cycling in limited-capacity Li batteries.