Stoichiometric Ti3C2Tx Coating for Inhibiting Dendrite Growth in Anode-Free Lithium Metal Batteries

Abstract

Lithium metal batteries (LMBs) and anode-free LMBs (AFLMBs) present a solution to the need for batteries with a significantly superior theoretical energy density. However, their adoption is hindered by low Coulombic efficiency (CE) and rapid capacity fading, primarily due to the formation of unstable solid electrolyte interphase (SEI) layer and Li dendrite growth as a result of uneven Li plating. Here, we report on the use of a stoichiometric Ti₃C₂T_x (S-Ti₃C₂T_x) MXene coating on the copper current collector to enhance the cyclic stability of an anode-free lithium metal battery. The S-Ti₃C₂T_x coating provides abundant nucleation sites, thereby lowering the overpotential for Li nucleation, and promoting uniform Li plating. Additionally, the fluorine (−F) termination of S-Ti₃C₂T_x participates in the SEI formation, producing a LiF-rich SEI layer, vital for stabilizing the SEI and improving cycle life. Batteries equipped with S-Ti₃C₂T_x@Cu current collectors displayed reduced Li consumption during stable SEI formation, resulting in a significant decrease in capacity loss. AFLMBs with S-Ti₃C₂T_x@Cu current collectors achieved a high initial capacity density of 4.2 mAh cm⁻², 70.9% capacity retention after 50 cycles, and an average CE of 98.19% in 100 cycles. This innovative application of MXenes in the energy field offers a promising strategy to enhance the performance of AFLMBs and could potentially accelerate their commercial adoption.