Multifunctional Properties of Al₂O₃/Polyacrylonitrile Composite Coating on Cu to Suppress Dendritic Growth in Anode-Free Li-Metal Battery

Abstract

The utilization of an anode-free lithium-metal battery (AFLMB) is pivotal in meeting the high-energy-density demand for portable electronic devices and vehicles. However, the dendritic growth of lithium (Li) and continuous SEI formation on Copper (Cu) current collector limits the lifetime of a cell. Here we report the effect of milled Al 2 O 3 /polyacrylonitrile (PAN) composite layer (AOP) coated on Cu, as AOP@Cu, to encourage compact and smoother Li + deposition extracted from NMC (333) cathode. The excellent wettable nature of the AOP layer promotes uniform ionic flux and improved kinetics. The multifunctional AOP layer offers moderate mechanical support and sufficient strength to the SEI layer to suppress dendritic growth. The formation of Li−Al−O/Al 2 O 3 species at the bottom part of the layer reveals AOP's lithiophilicity to form new SEI components, besides Al−F, by regulating Li + deposition. PAN synergism is manifested by its flexible binding role and nitrogen content that has an excellent affinity to Li + . The resulting AOP@Cu||NMC and AOP@Cu||Li cells demonstrated improved cycling stability and Coulombic efficiency. An AOP@Cu||NMC cell run at 0.2 mA cm −2 exhibits a first cycle discharge capacity of 160 mAh g −1 that retains 30% after 82 cycles, whereas the Cu||NMC cell retains ∼30% after only 52 cycles.

What Can be Expected from “Anode‐Free” Lithium Metal Batteries?

“…[18] Surface modification with Cu 3 N, Al 2 O 3 , Ag-C nanoparticles, among others, adds a thin film that functions as a primer layer, increasing surface wettability and promoting more nucleation sites for Li. [17,19,20] Although engineered to minimize the growth of Li protrusions, one advantage of using this strategy for anode-free cells is the ability to increase the compactness of the initial deposited Li layer, thus reducing Li metal surface area which helps stabilize the SEI. Works on preplated or prestripped Li metal suggest that the initial Li morphology is linked to a higher chance of dendrite production or longer cycle life.…”

Porous Lithiophilic Li–Si Alloy‐Type Interfacial Framework via Self‐Discharge Mechanism for Stable Lithium Metal Anode with Superior Rate

“…The CV results suggest that the introduction of LSIF led to more effective current distribution and enhanced electrochemical redox activity accompanied with improving charge transfer kinetics. [ 32 ] In particular, the LSIF@Li||Cu cells presented a clean sweep of the CV curve with “no Li intercalation” regions except for the typical Li plating/stripping peaks. This result confirmed that LSIF does not cause uncontrollable side reactions with Li and that LSIF@Li behaves like a metallic Li anode while remaining compositionally invariant upon Li plating/stripping.…”

From Lithium‐Metal toward Anode‐Free Solid‐State Batteries: Current Developments, Issues, and Challenges

“…[82] Recently, multifunctional coatings, such as an Al 2 O 3 /Polyacrylonitrile (PAN) composite were reported, exploiting combined benefits of the inorganic and the organic component. [83] While Al 2 O 3 results in the formation of conductive Li-Al-O and SEIforming Al-F species, the flexible nature of PAN provides mechanical stability and nitrogen content improves the affinity toward Li.…”