Continuous plating/stripping behavior of solid-state lithium metal anode in a 3D ion-conductive framework

Abstract

The increasing demands for efficient and clean energy-storage systems have spurred the development of Li metal batteries, which possess attractively high energy densities. For practical application of Li metal batteries, it is vital to resolve the intrinsic problems of Li metal anodes, i.e., the formation of Li dendrites, interfacial instability, and huge volume changes during cycling. Utilization of solid-state electrolytes for Li metal anodes is a promising approach to address those issues. In this study, we use a 3D garnet-type ion-conductive framework as a host for the Li metal anode and study the plating and stripping behaviors of the Li metal anode within the solid ion-conductive host. We show that with a solid-state ion-conductive framework and a planar current collector at the bottom, Li is plated from the bottom and rises during deposition, away from the separator layer and free from electrolyte penetration and short circuit. Owing to the solid-state deposition property, Li grows smoothly in the pores of the garnet host without forming Li dendrites. The dendrite-free deposition and continuous rise/fall of Li metal during plating/stripping in the 3D ion-conductive host promise a safe and durable Li metal anode. The solid-state Li anode shows stable cycling at 0.5 mA cm for 300 h with a small overpotential, showing a significant improvement compared with reported Li anodes with ceramic electrolytes. By fundamentally eliminating the dendrite issue, the solid Li metal anode shows a great potential to build safe and reliable Li metal batteries.

Thick Electrode Batteries: Principles, Opportunities, and Challenges

“…By changing the laminated structure or laminated layering of the garnet taps, tri‐layer SSEs with a porous/dense/porous architecture and diverse thicknesses are also achieved . Based on these 3D SSEs, diverse Li‐metal electrodes or Li‐metal batteries with high active material loading and improved energy density have been further reported . For example, a hybrid Li‐S cell with a sulfur loading of 7.5 mg cm −2 was demonstrated based on the bilayer SSE, which achieved a high energy density of 248.2 Wh kg −1 and average Coulombic efficiency over 99% .…”

High‐Rate and Large‐Capacity Lithium Metal Anode Enabled by Volume Conformal and Self‐Healable Composite Polymer Electrolyte

“…[3,4] However, the successful implementation of Li metal has been impeded due to the poor control of electrodeposition during the Li plating/stripping cycling, a consequence of which is the formation of mossy or dendritic lithium that can penetrate the separator, cause an internal short-circuit, and eventually lead to battery thermal runaway. [20][21][22][23][24] However, the performances at high current densities with high areal capacities over long cycling have not been fully explored. Moreover, unlike graphite anode that only have ≈10% volume change during lithiation/delithiation intercalation processes, Li metal is a "hostless" electrode with a virtually infinite volume change, resulting in significant internal stress accumulation, SEI collapse and high interfacial impedance upon prolonged cycling.…”

Interfacial Incompatibility and Internal Stresses in All‐Solid‐State Lithium Ion Batteries

“…Hu's group, [196,227] has shown to be a promising approach. Some buffering layers, i.e., Nb, NbO 2 , and Li 2 BO 3 , have been successfully applied, precluding the production of insulating phases.…”

“…For the ceramic-metal system, the wettability behavior should be accompanied by the decrease of systematic Gibbs free energy caused by mass transfer taking place at the interface. [196] Briefly, four factors mentioned contribute to large resistance at the SSE/Li interfaces, producing a large polarization upon charging and discharging. Dissolution can decrease the surface tension of the liquids, making the liquids spread on the solids smoothly.…”