Cool cubes: Zn,Co-containing N-doped porous carbon nanocube (Zn/Co−N@PCN) can be directly applied as a lithiophilic host to predeposit Li to prepare a Li−Zn/Co−N@PCN anode. The symmetric battery with Li−Zn/Co−N@PCN electrode exhibits excellent lifespan. Moreover, the Li−O2 full battery with the Li−Zn/Co−N@PCN based anode exhibits superior electrochemical performance.
Li metal, because of its ultrahigh theoretical capacity, has attracted extensive attention. However, uncontrollable dendritic Li formation and infinite electrode dimensional variation hinder application of Li anodes. Herein, Zn,Co bimetallic zeolitic imidazolate frameworks (ZIFs) were synthesized and further pyrolyzed to obtain Zn,Co-containing N-doped porous carbon nanocube (Zn/Co−N@PCN), which was further applied as lithiophilic host to construct the lithiated Zn/Co−N@PCN (Li−Zn/Co−N@PCN). Zn vapor produced many pores on the carbon framework during calcination process that could store enough Li and thus inhibit the huge electrode volume change. Additionally, there were abundant lithiophilic groups in Zn/Co−N@PCN, such as N- or Co/Zn-based species, which were beneficial to uniform Li deposition. Moreover, the stable and conductive carbon-based matrix could ensure superior and reproducible Li plating/stripping behavior in Zn/Co−N@PCN over cycling. As a result, the Li−Zn/Co−N@PCN anode showed a steady and high columbic efficiency of around 99.0 % for 600 cycles at 0.5 mA cm−2. The Li−Zn/Co−N@PCN-based Li−O2 battery could continuously work beyond 200 cycles, superior to a cell with a Li−Cu anode. These results in this work provide a novel way for construction of the advanced Li-based anodes and the corresponding high-performance Li−O2 batteries.Zum Volltext