Lithiophilic ZnO confined in microscale carbon cubes as a stable host for lithium metal anodes

The high energy density metallic Li anode is a desired electrode candidate for commercial application in future. However, uncontrolled growth of Li dendrites can easily lead to thermal runaway and infinite volume changes. Herein, we propose the addition of lithiophilic ZnO filled into the microsized cubic carbon framework through in situ pyrolyzation of the multiwalled carbon nanotubes-implanted Zn-MOF (denoted as ZnO@C-MWCNTs) as the three-dimensional (3D) host for stable metallic Li anodes. The proposed 3D host with a high specific surface area can effectively accommodate the tremendous volume change of the metallic Li anodes. Meanwhile, this 3D host can prohibit the emergence of Li dendrites by adjusting the local current density. Lithiophilic ZnO, as the homogeneous nucleation site loaded in the 3D structure, can induce homogeneous Li deposition to form a stable Li metal composite electrode with a long cycling life. The 3D ZnO@C-MWCNTs host can hold a high Coulombic efficiency (CE) of 98.5% at 1.0 mA cm-2 and 1.0 mAh cm-2 for more than 240 cycles. Long lifespans of symmetric cells for 320 h at 2.0 mA cm-2 and 1.0 mAh cm-2 with a lower polarization (~28.0 mV) can be achieved.

Automated summary

In this study, a three-dimensional host structure composed of lithiophilic ZnO-filled microsized carbon framework was proposed for stable metallic Li anodes. The host structure can effectively accommodate volume changes and inhibit dendrite growth, leading to a stable Li metal composite electrode. Experimental results demonstrate that this host structure exhibits high Coulombic efficiency and long cycling life.