Constructing Artificial SEI Layer on Lithiophilic MXene Surface for High‐Performance Lithium Metal Anodes

Abstract

MXene has been found as a good host for lithium (Li) metal anodes because of its high specific surface area, lithiophilicity, good stability with lithium, and the in situ formed LiF protective layer. However, the formation of Li dendrites and dead Li is inevitable during long‐term cycle due to the lack of protection at the Li/electrolyte interface. Herein, a stable artificial solid electrolyte interface (SEI) is constructed on the MXene surface by using insulating g‐C3N4 layer to regulate homogeneous Li plating/stripping. The 2D/2D MXene/g‐C3N4 composite nanosheets can not only guarantee sufficient lithiophilic sites, but also protect the Li metal from continuous corrosion by electrolytes. Thus, the Ti3C2Tx/g‐C3N4 electrode enables conformal Li deposition, enhanced average Coulombic efficiency (CE) of 98.4%, and longer cycle lifespan over 400 cycles with an areal capacity of 1.0 mAh cm−2 at 0.5 mA cm−2. Full cells paired with LiFePO4 (LFP) cathode also achieve enhanced rate capacity and cycling stability with higher capacity retention of 85.5% after 320 cycles at 0.5C. The advantages of the 2D/2D lithiophilic layer/artificial SEI layer heterostructures provide important insights into the design strategies for high‐performance and stable Li metal batteries.

Li2CO3/LiF‐Rich Heterostructured Solid Electrolyte Interphase with Superior Lithiophilic and Li+‐Transferred Characteristics via Adjusting Electrolyte Additives

“…[9][10][11] Therefore, high-quality SEI is highly desired for superior LMBs.Recently, extensive efforts have been devoted to stabilizing Li anode by engineering a robust SEI mainly through electrolyte formulation [12][13][14][15][16] and artificial SEI. [17][18][19][20] However, the role of the structures and components of SEI has long been debated, and the transport mechanism of Li + ions in the SEI is still not well understood. [21] Theoretically, an ideal SEI layer should have high ionic conductivity to ensure a fast Li + transport across the SEI, and a good electron insulator to prevent electron tunneling from the Li anode to the SEI, [21][22][23] which can ensure the Li deposition occurred at the SEI/Li interface.…”

Surface-Termination Groups’ Tuning to Improve the Lithium-Ion-Storage Performance of Ti3C2Tx MXene

“…The chemically active lithium-storage sites were continuously activated, resulting in an increase in the pseudocapacitance contribution of the electrode surface. In future work, the following methods could be used to improve the ICE of the electrode: short-circuiting the negative pole piece by electrical contact with the short-circuit method, adjusting the resistance and processing time of the short-circuit wire, and realizing prelithiation under the action of the potential difference; using lithiumaromatic compounds (lithium naphthalene, butyllithium) to immerse or spray the negative electrode material to achieve chemical prelithiation [39,40]; functionally modifying the metal electrode with the help of artificial SEI layer technology to improve the ICE [41].…”

Three-Dimensional Carbon Foam Modified with Mg3N2 for Ultralong Cyclability of a Dendrite-Free Li Metal Anode

“…Rechargeable batteries as energy storage devices play an important role in modern society. − However, traditional lithium-ion batteries (LIBs) with graphite as an anode cannot meet the rapidly increasing market demand due to their low energy density. , Lithium metal is known as the “Holy Grail” electrode based on its high theoretical specific capacity (3860 mAh g –1 ), lowest density (0.534 g cm –3 ), and low electrode potential (−3.04 V), , which has been applied in lithium–sulfur and lithium–air batteries with the high energy density of more than 2000 Wh kg –1 . , However, the present lithium metal anode faces two main challenges: on the one hand, the “hostless” characteristic of lithium metal is strongly inclined to grow as lithium dendrites during the deposition process, resulting in the generation of “dead Li”, internal short circuit, and even fire; − on the other hand, the infinite volume fluctuation during the deposition/stripping processes will cause the rupture of the solid electrolyte interphase (SEI), leading to unstable interfacial structures and deterioration of the electrochemical properties, − impeding the practical application of the lithium metal anode.…”