Built-In Stable Lithiophilic Sites in 3D Current Collectors for Dendrite Free Li Metal Electrode

Stable lithiophilic sites in 3D current collectors are the key to guiding the uniform Li deposition and thus suppressing the Li dendrite growth, but such sites created by the conventional surface decoration method are easy to be consumed along with cycling. In this work, carbon fiber (CF)-based 3D porous networks with built-in lithiophilic sites that are stable upon cycling are demonstrated. Such heterostructured architecture is constructed by the introduction of zeolitic imidazolate framework-8-based nanoparticles during the formation of the 3D fibrous carbonaceous network and the following annealing. The introduced Zn species are found to be re-distributed along the entire individual CF in the 3D network, and function as lithiophilic sites that favor the homogenous lithium nucleation and growth. The 3D network also presents a multi-scale porous structure that improves the space utilization of the host. The corresponding symmetric cells adopting such 3D anode demonstrate excellent cycling performance, especially at a high rate (300 cycles at 10 mA cm(-2) with a capacity of 5 mA h cm(-2)). A full cell with LiFePO4 cathode shows a capacity retention of 98% after cycling at 1C for 300 cycles. This method provides an effective design strategy for 3D hosting electrodes in dendrite-free alkali metal anode applications.

Automated summary

This study demonstrates a 3D porous network based on carbon fiber with stable lithiophilic sites during cycling. The introduced zinc species are redistributed throughout the network and function as lithiophilic sites for uniform lithium nucleation and growth. The 3D network also has a multi-scale porous structure that improves the space utilization of the electrode. The symmetric cells based on this 3D anode exhibit excellent cycling performance, especially at high rates.