Design of Robust, Lithiophilic, and Flexible Inorganic‐Polymer Protective Layer by Separator Engineering Enables Dendrite‐Free Lithium Metal Batteries with LiNi_0.8Mn_0.1Co_0.1O₂ Cathode

Abstract

As a promising candidate for the high energy density cells, the practical application of lithium-metal batteries (LMBs) is still extremely hindered by the uncontrolled growth of lithium (Li) dendrites. Herein, a facile strategy is developed that enables dendrite-free Li deposition by coating highlylithiophilic amorphous SiO microparticles combined with high-binding polyacrylate acid (SiO@PAA) on polyethylene separators. A lithiated SiO and PAA (lithiated-SiO/PAA) protective layer with synergistic flexible and robust features is formed on the Li metal anode via the in situ reaction to offer outstanding interfacial stability during long-term cycles. By suppressing the formation of dead Li and random Li deposition, reducing the side reaction, and buffering the volume changes during the lithium deposition and dissolution, such a protective layer realizes a dendrite-free morphology of Li metal anode. Furthermore, sufficient ionic conductivity, uniform lithiumion flux, and interface adaptability is guaranteed by the lithiated-SiO and Li polyacrylate acid. As a result, Li metal anodes display significantly enhanced cycling stability and coulombic efficiency in Li||Li and Cu||Li cells. When the composite separator is applied in a full cell with a carbonate-based electrolyte and LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathode, it exhibits three times longer lifespan than control cell at current density of 5 C. dominate the major energy-storage markets over the past decades. Unfortunately, the highest energy density that the conventional LIBs can output is far from the demands of emerging high-energy applications, such as long-range electric vehicles and autonomous aircrafts. [1-4] Accordingly, lithium metal batteries (LMBs) are deemed to be a promising candidate for the nextgeneration batteries on account of the excellent advantages of Lithium (Li) metal anode accompanied with the highest theoretical specific capacity (3860 mAh g −1) and the lowest redox potential (−3.04 V versus the standard hydrogen electrode). [5,6] However, the practical application of Li metal anodes has been greatly limited, mainly because of the uncontrolled growth of Li dendrites in the charge/discharge process, bring about capacity fade and even serious security issues. [7,8] During cell operation, the objective micro-roughness of Li electrode surfaces causes an inhomogeneous distribution of Li ions flux and followed by the formation of Li dendrite. The resulting Li dendrite gradually growth during plating/stripping processes, tends to impale the separator leading to an internal short-circuit sometimes with fire or explosion. [9] The dendritic Li easily snaps off and generates the inactive Li so-called "dead Li", also leads to capacity attenuation of the batteries. [10] Moreover, Li metal can react spontaneously with any liquid electrolyte, which results in a heterogeneous and fragile solid electrolyte interphase (SEI) layer instantly forming on the surface of Li metal anode. [11] Unfortunately, during Li plating, the brittle SEI is easily destroyed by stress...

Morphological Control: Properties and Applications of Metal Nanostructures

“…Unlike soft mold synthesis, hard molded metal nanowires usually have a polycrystalline or polycrystalline structure. Since the magnetic nature of nanomaterials strongly depends on the degree of crystallinity of the structure, subsequent annealing heat treatment is usually used to improve the magnetic properties of nanowires produced by hard molding [97,98]. Here, the porous alumina mold acts as a protective mold during the annealing operation of nanowires due to its high chemical and thermal stability [99,100].…”

Mechanism understanding for stripping electrochemistry of Li metal anode

“…Even dendrite-free Li metal anode can lead to dead Li in the stripping process, which will be clearly discussed in the following sections. 109 The formation of dead Li during plating/stripping process has hindered the practical applications of Li metal in rechargeable batteries based on the following reasons [110][111][112][113][114][115] : (1) Since dead Li is electrochemically inactive during further reaction, it directly leads to the rapid capacity degradation and lowers the Coulombic efficiency of batteries. (2) The dead Li accumulation at Li anodes introduces a tortuous diffusion pathway and an exponential increase of resistance for Li ions and electrons inevitably.…”

Interface engineering towardhigh‐efficiencyalloy anode for next‐generation energy storage device

“…The past decades have witnessed a growing demand for developing energy storage devices with higher energy density, owing to the soaring development of the electric vehicles (EVs) market 1–5 . Alkali metal batteries, especially lithium‐ion batteries have been widely applied as electrochemical energy storage devices attributed to their renewability, safety, and cyclic stability 6–8 .…”