A dual-functional DMDAAC electrode enhancer with hydrophobic effect for highly stable Zn powder composite anode

Abstract

MXene-modified zinc powder (MXene@Zn-p) anodes have demonstrated the unique effect of inhibiting dendrite growth, thereby enhancing interface stability. However, the insufficient binding force between Ti₃C₂T_x MXene and Zn powder, endowed with natural hydrophilicity, results in an inevitable failure of MXene@Zn-p anodes during long-term cycles. To address this issue, Dimethyl Diallyl Ammonium Chloride (DMDAAC) is introduced as a dual-functional electrode enhancer to construct a tight hydrophobic interface on the Zn powder composite anode by electrostatic self-assembly while effectively solving the weak adhesion and hydrophilicity of both MXene and Zn powder. The obtained Zn powder composite anode effectively suppresses dendrite growth and corrosion effects, achieving a durable interfacial stability. The DFT and COMSOL simulations further certify that the DMDAAC plays a key role in regulating uniform Zn deposition. As a result, the as-engineered anode achieves a high coulombic efficiency of 99.2% after 300 cycles at 1 mA cm^-2. Symmetric cells with the composite Zn powder anode demonstrates stble cycling for 300 h at 1 mA g^-1 and 1 mA h g^-1, extending lifespan by 233 h compared with MXene@Zn-p anode. The assembled two full cells with Zn powder composite anode also exhibit reamrkably high capacity retention and cycling stability (89.8% after 200 cycles at 5 A·g^-1 for MnVO and 82.2% after 1000 cycles at 1 A·g^-1 for MnO₂). This work provides an efficient strategy for achieving highly stable Zn powder composite anode, thus facilitating the commercialization process of aqueous zinc ion batteries.