Interface Engineering via Ti3C2Tx MXene Electrolyte Additive toward Dendrite-Free Zinc Deposition

Abstract

Zinc metal batteries have been considered as a promising candidate for next-generation batteries due to their high safety and low cost. However, their practical applications are severely hampered by the poor cyclability that caused by the undesired dendrite growth of metallic Zn. Herein, Ti3C2Tx MXene was first used as electrolyte additive to facilitate the uniform Zn deposition by controlling the nucleation and growth process of Zn. Such MXene additives can not only be absorbed on Zn foil to induce uniform initial Zn deposition via providing abundant zincophilic-O groups and subsequently participate in the formation of robust solid-electrolyte interface film, but also accelerate ion transportation by reducing the Zn2+ concentration gradient at the electrode/electrolyte interface. Consequently, MXene-containing electrolyte realizes dendrite-free Zn plating/striping with high Coulombic efficiency (99.7%) and superior reversibility (stably up to 1180 cycles). When applied in full cell, the Zn-V2O5 cell also delivers significantly improved cycling performances. This work provides a facile yet effective method for developing reversible zinc metal batteries.

Manipulating Crystallographic Orientation of Zinc Deposition for Dendrite‐free Zinc Ion Batteries

“…Remarkably, the surface of CG separator presents a much higher Zeta potential of −28.9 mV than that of cellulose separator (−13.4 mV) (Figure S7b, Supporting Information), related to the abundant oxygen‐containing (O) groups of graphene oxide (Figure S7c, Supporting Information), including OH (3440 cm –1 ), COOH (1639 cm –1 ), COH (1368 cm –1 ), COC (1033 cm –1 ). [ 58–61 ] And the negative surface charges can lead to the closely adhesion between zinc anode and CG separator under the electrostatic attraction and strong binding energy between O groups and zinc anode (OH/Zn: −7.64 eV, O/Zn: −26.33 eV), [ 62 ] which greatly shortens the path of Zn 2+ ions transmission and constructs a special separator–anode interface. [ 62,63 ] Additionally, the negative charged CG separator surface can effectively deanion (SO 4 2– ) via the electrostatic repulsion, [ 64 ] thus suppressing the formation of side effects (Zn 4 SO 4 (OH) 6 ·5H 2 O), which is demonstrated in Figure S7d, Supporting Information.…”

“…[ 58–61 ] And the negative surface charges can lead to the closely adhesion between zinc anode and CG separator under the electrostatic attraction and strong binding energy between O groups and zinc anode (OH/Zn: −7.64 eV, O/Zn: −26.33 eV), [ 62 ] which greatly shortens the path of Zn 2+ ions transmission and constructs a special separator–anode interface. [ 62,63 ] Additionally, the negative charged CG separator surface can effectively deanion (SO 4 2– ) via the electrostatic repulsion, [ 64 ] thus suppressing the formation of side effects (Zn 4 SO 4 (OH) 6 ·5H 2 O), which is demonstrated in Figure S7d, Supporting Information. Furthermore, the electrochemical impedance spectrum (EIS) proves that the fast ion diffusion and quick charge transfer process can be achieved by CG separator (Figure 3d).…”

“…Remarkably, a ZnO bond can be detected in CG separator after soaking in ZnSO 4 electrolyte (Figure S12a, Supporting Information), indicative of the strong interaction between oxygen‐containing groups and Zn 2+ , where the Zn 2+ can be easily absorbed on the O groups and adjust the Zn 2+ distribution in the separator–anode interface, thus promoting the uniform nucleation. [ 62 ] In a sharp contrast, no apparent changes observed in the O 1s spectra of cellulose separator after soaking (Figure S12b, Supporting Information). Additionally, it is obvious that the CG separator possessed a highly stable CE (98.69%) comparing with cellulose separator over 200 cycles (Figure 3g), indicating the CG separator can enhance the sustainability or reversibility of Zn anode and prolong its lifespan.…”

MOF-Derived ZnS Nanodots/Ti3C2Tx MXene Hybrids Boosting Superior Lithium Storage Performance

“…Several conductive matrixes including graphene [5,6,16], porous carbon [17,20,21], and carbon nanotubes [22] were adopted to combine with ZnS for improving electrochemical performance. MXenes, a new family of the 2D materials, have already been proved to be promising candidate as electrode materials for electrochemical energy storage devices [23][24][25][26][27][28][29][30][31], such as LIBs and supercapacitors. Among the large family of MXenes, Ti 3 C 2 T x [32] is the most widely studied one for electrochemical energy storage owing to its high electronic conductivity (up to 2.4 × 10 4 S cm −1 ) [33], hydrophilic surfaces and high density [34].…”

Interfacial Engineering Strategy for High-Performance Zn Metal Anodes

“…Both Zn dendrites and side reactions are closely related to the Zn anode interface toward the electrolyte. Interfacial engineering, including surface coating and the addition of electrolyte additives, is an effective strategy to regulate the deposition behavior of Zn ions and the effect of water molecules, which effectively alleviate Zn dendrite growth and the Zn anode side reactions [54][55][56][57]. Surface coatings can reduce direct contact between the Zn anode and water molecules in the electrolyte, inhibiting side reactions on the Zn anode surface.…”