Spatially Confined Li Growth on Honeycomb-like Lithiophilic Layered Double Hydroxide Nanosheet Arrays toward a Stable Li Metal Anode

Abstract

A lithium metal anode (LMA) is appealing due to its high theoretical capacity and low electrochemical potential. Unfortunately, the practical application of LMAs is restricted by the uncontrollable Li dendrite growth and tremendous volume change. Herein, lithiophilic honeycomb-like layered double hydroxide (LDH) nanosheet arrays supported on a flexible carbon cloth (NiMn-LDHs NAs@CC) are synthesized as the Li host to spatially confine the Li deposition, guiding Li growth via a conformal and uniform manner. First, the lithiophilic NiMn-LDHs NAs as nucleation seeds render the CC substance outstanding lithiophilicity and reduce the nucleation barrier. The hierarchical honeycomb-like structure then directs the oriented Li deposition and provides an open channel for fast ion transport. Finally, the CC skeleton offers a high specific surface for decreasing the inhomogeneous distribution of the current density and enough space for alleviating the volume variations, synergistically inhibiting the dendritic Li growth. As a consequence, the NiMn-LDHs NAs@CC symmetric cell exhibits a low overpotential of less than 17 mV at 2 mA cm −2 and a long lifespan of 2100 h at 3 mA cm −2 . In addition, when paired with the LiNiCoMnO 2 (NCM111) cathode, the NiMn-LDHs NAs@CC@Li full cell presents enhanced cycling stability and rate capability in comparison to the CC@Li full cell, implying the great potential of the NiMn-LDHs NAs@CC in stabilizing the LMA.

Review of Nanoarrays in Lithium Metal Anodes

“…Meanwhile, LDHs can be easily grown vertically on a variety of substrates to accelerate Li + diffusion. − All the above features are consistent with the material requirements of a vertical array of current collectors and are valid orientations. Due to these advantages, NiMn layered double hydroxides nanosheet arrays (NiMn-LDHs NAs) were developed in a recent study by Tao et al on carbon cloth substrates to inhibit the growth of Li dendrites. During the initial discharge process, NiMn-LDHs react with Li to form metallic Mn and Mn x O y nanoparticles, which further enhance the lithiophilicity of the substrate.…”

“…147−149 All the above features are consistent with the material requirements of a vertical array of current collectors and are valid orientations. Due to these advantages, NiMn layered double hydroxides nanosheet arrays (NiMn-LDHs NAs) were developed in a recent study by Tao et al 150 4e). Meanwhile, the TFSI − in the electrolyte of 1.0 M LiTFSI in DOL/DME (1:1, v/v) with 1% LiNO 3 provided more Li + in the strong electrostatic interaction with NiFe-LDH, and O−H covalent bonds are formed between the O of TFSI − and H in LDH, which accelerates the transfer of Li + and provides higher ionic conductivity under the action of NiFe-LDH and electrolyte, and Li + penetrates more easily into the interior of the 3D structure.…”

“…(d) Li growth along the texture of NAs then deposits into the gaps between the nanosheets and is able to completely restore the original hierarchical structure after being stripped. Reproduced with permission from ref . Copyright 2022 American Chemical Society.…”