Dendrite‐Free Reverse Lithium Deposition Induced by Ion Rectification Layer toward Superior Lithium Metal Batteries

Abstract

Considerable endeavors are developed to suppress lithium (Li) dendrites and improve the cycling stability of Li metal batteries in order to promote their commercial application. Herein, continuous zinc (Zn) nanoparticles‐assembled film with homogenous nanopores is proposed as a modified layer for separator via a scalable method. The in situ formed LiZn alloy film during initial Li plating can serve as a Li+ ion rectification and lithiophilic layer to regulate the nucleation and reverse deposition of Li. When applied in Li|LiFePO4 full cells with traditional carbonate‐based electrolyte, the modified separator enables outstanding cycling stability of up to 350 cycles without capacity loss at a large rate of 5 C (3.4 mA cm−2) and a remarkable reversible capacity of 144 mAh g−1 after 120 cycles at a commercial mass loading as high as 19.72 mg cm−2. The excellent electrochemical performances are ascribed to the dendrite‐free reverse Li deposition induced by modified layer by means of its lithiophilic property for regulating homogeneous Li nucleation on the separator as well as its well‐distributed nanopores for homogenizing Li+ ion flux and enhancing electrolyte wetting.

CuCl2‐Modified Lithium Metal Anode via Dynamic Protection Mechanisms for Dendrite‐Free Long‐Life Charging/Discharge Processes

“…[28] The duration of protection provided by ZnCl 2 /Li (80 h, current density: 4 mA cm −2 , capacity: 2 mA h cm −2 ) is similar to that of sample 0.05-Zn-PP in Lin's report (80 h, current density: 3 mA cm −2 , capacity: 1 mA h cm −2 ). [29] In Lin's work, the best sample of 0.25-Zn-PP achieved stable cycling over 600 h at the current density of 3 mA cm −2 , which are attributed to effective regulation of Li + ion flux by porous Li-Zn alloy layer. Without porous structure and sufficient alloy phase, it is difficult for ZnCl 2 /Li to maintain a continuous protective effect.…”

Adjustable Mixed Conductive Interphase for Dendrite-Free Lithium Metal Batteries

“…Moreover, the denser and thinner interphase is adverse to the electrolyte wettability and mechanical strength. And the thicker interphase also prolongs the distance of ion migration . Therefore, as shown in Figure f, the MIEC interphase with appropriate Zn/O ratio (Zn-ZnO-M), thickness, and nanopore size can reap the superior interface kinetics (highest D Li+ and lowest R SEI + R ct ).…”

“…This is because the more severe passivation on the surface of the Zn target caused by increasing oxygen content needs a higher sputtering voltage and a lower current to maintain constant sputtering power, which brings sufficient energy and time for the surface migration of ZnO nanoparticles, further densifying the Zn-ZnO film. The uniform nanopores can be observed in top- and side-view SEM images of Zn-ZnO-M (Figure a,b), which can relieve volume expansion during activation and Li plating …”

“…It is demonstrated that the introduction of electronic conductive alloy phases in the interphase contributes to buffering the Li + ion concentration gradient, strengthening mechanical stability, and reducing activation energies at various solid/liquid interfaces, such as a Li 0.35 La 0.52 [V] 0.13 TiO 3 /Li hybrid layer, a Sn–Li hybrid layer, and halid–alloy hybrid layers. ,,,− Although Li + ions would still transport uniformly across a pure electronic conductive interphase by means of its porous structure, the participation of electronic conductive constituents would reduce the driving force of Li diffusion owing to the low potential gradient, which may lead to insufficient Li + diffusion under a high current density . So it is desirable to optimize the charge transfer while ensuring the ion diffusion in the interphase, focusing on the kinetics properties of the interphase based on the trade-off between ionic and electronic conductivity.…”

“…9,13,18,20−24 Although Li + ions would still transport uniformly across a pure electronic conductive interphase by means of its porous structure, the participation of electronic conductive constituents would reduce the driving force of Li diffusion owing to the low potential gradient, which may lead to insufficient Li + diffusion under a high current density. 25 So it is desirable to optimize the charge transfer while ensuring the ion diffusion in the interphase, focusing on the kinetics properties of the interphase based on the trade-off between ionic and electronic conductivity.…”