Recent Advances of Emerging 2D MXene for Stable and Dendrite‐Free Metal Anodes

Abstract

Metal anodes based on a plating/stripping electrochemistry such as metallic Li, Na, K, Zn, Mg, Ca, Al, and Fe have attracted widespread attention over the past several years because of their high theoretical specific capacity, low electrochemical potential, and superior electronic conductivity. Metal anodes can be paired with cathodes to construct high-energy-density rechargeable metal batteries. However, inherent issues including large volume changes, uncontrollable growth of dangerous dendrites, and an unstable solid electrolyte interphase (SEI) hinder their further development. MXene as an emerging 2D material has shown great potential to address the inherent issues of metal anodes due to its 2D structure, abundant surface functional groups, and the ability to construct macroscopic architectures. To date, under the assistance of MXene, various strategies have been proposed to achieve stable and dendrite-free metal anodes, such as MXene-based host design, designing metalphilic MXene-based substrates, modifying the metal surface with MXene, constructing MXene arrays, and decorating separators or electrolytes with MXene. Herein the applications and advances of MXene in stable and dendrite-free metal anodes are carefully summarized and analyzed. Some perspectives and outlooks for future research are also proposed.

An Overview of Recent Advances in the Synthesis and Applications of the Transition Metal Carbide Nanomaterials

“…When excess ZnCl 2 is used, a Cl-terminated MXene is obtained, like Ti 2 CCl 2 and Ti 3 C 2 Cl 2 . Thus, these Lewis acidic melts could etch Al from MAX phases providing a variety of MXene based on redox-controlled mechanisms [ 43 ]. It is found that the lattice parameters of MXene etched by salt are greater than the one etched by acid and the layer spacing is also increased in salt-etched MXene [ 44 ].…”

“…In this process Cl - rapidly etch Al because of its strong binding ability. The cations intercalate and increase the d-spacing [ 43 ].…”

Status and Prospects of MXene‐Based Lithium–Sulfur Batteries

“…An ideal Li host should be 1) lightweight, robust, and porous to accommodate Li; 2) electrochemically stable during the Li plating/stripping processes; 3) highly conductive and has low Li + diffusion energy barrier to achieve rapid electrochemical kinetics; and 4) lithiophilic to guarantee the efficient combination with Li and guide its nucleation. [ 12 ]…”

“…Great efforts have been made in recent decades to overcome these problems, including physically confining sulfur in porous carbons, [ 6a,9 ] chemically bonding LiPSs by polar metal compounds, [ 10 ] inserting a conductive interlayer between cathode and separator, [ 11 ] and designing advanced Li anode to suppress the dendrite growth. [ 12 ] Based on these strategies, the above‐mentioned issues are somewhat mitigated, but the Li–S batteries’ commercial application has not yet been realized.…”

Mechanisms of the Planar Growth of Lithium Metal Enabled by the 2D Lattice Confinement from a Ti3C2Tx MXene Intermediate Layer

“…Recently, 2D materials, such as graphene, [ 14 ] h‐BN, [ 15 ] and MXenes, [ 16 ] have been investigated as scaffolds or substrates for Li metal anodes. Especially, 2D transition metal carbides known as MXenes have attracted attention in capacitor and battery research due to their metallic electrical conductivity, [ 17 ] exceeding that of solution processed graphene.…”