Atomically dispersed cobalt catalyst anchored on nitrogen-doped carbon nanosheets for lithium-oxygen batteries

Abstract

Developing single-site catalysts featuring maximum atom utilization efficiency is urgently desired to improve oxidation-reduction efficiency and cycling capability of lithium-oxygen batteries. Here, we report a green method to synthesize isolated cobalt atoms embedded ultrathin nitrogen-rich carbon as a dual-catalyst for lithium-oxygen batteries. The achieved electrode with maximized exposed atomic active sites is beneficial for tailoring formation/decomposition mechanisms of uniformly distributed nano-sized lithium peroxide during oxygen reduction/evolution reactions due to abundant cobalt-nitrogen coordinate catalytic sites, thus demonstrating greatly enhanced redox kinetics and efficiently ameliorated over-potentials. Critically, theoretical simulations disclose that rich cobalt-nitrogen moieties as the driving force centers can drastically enhance the intrinsic affinity of intermediate species and thus fundamentally tune the evolution mechanism of the size and distribution of final lithium peroxide. In the lithium-oxygen battery, the electrode affords remarkably decreased charge/discharge polarization (0.40 V) and long-term cyclability (260 cycles at 400 mA g−1).

Mesoporous Carbons from Polysaccharides and Their Use in Li-O2 Batteries

“…However, in the case of the carbon obtained from chitosan, although the mesoporosity is lower, the capacity was the highest achieved. In this case, the effect of the presence of nitrogen clearly improves the performance of the material, as already described in the literature [ 31 , 32 , 33 , 34 ].…”

Recent Advances in Single-Atom Electrocatalysts for Oxygen Reduction Reaction

“…Yan et al further found that Pt 2 dimers could also be deposited on graphene with ALD technology [86]. As shown in Figure 4( [89,102] could release metal atom vapor, which could be trapped by various substrates placed in the downstream and form corresponding SAECs. For example, Nb atom vapor released by arc discharge of Nb bulk could be trapped by carbon and formed the single-atom Nb-in-C catalyst [99].…”

“…Atom trapping method is a newly developed strategy to synthesize SAECs. At high temperatures, metal nanoparticles (Pt, Pd, Au, Rh, and Ni nanoparticles) [ 88 , 97 , 98 ], metal bulks (Pt net, Au foil, Pd bulk, Nb bulk, Cu foam, Co foam, and Ni foam) [ 99 – 101 ], metal oxides (Fe 2 O 3 , Co 2 O 3 , Cu 2 O, SnO 2 , and MoO 3 ) [ 87 ], and metal salts (CoCl 2 , H 2 PtCl 6 , H 2 PdCl 4 , HAuCl 4 , and H 2 IrCl 6 ) [ 89 , 102 ] could release metal atom vapor, which could be trapped by various substrates placed in the downstream and form corresponding SAECs. For example, Nb atom vapor released by arc discharge of Nb bulk could be trapped by carbon and formed the single-atom Nb-in-C catalyst [ 99 ].…”

“…" , which resulted in the decreased fraction of Li 2 O 2 in the final discharge products. Coupling with the merits of 2D MOFs and atomically dispersed metal sites, the Co-SAs/N-C catalyst could be used as the cathode catalyst for Li-O 2 battery [89], delivers low-impedance charge transfer pathways, and provides large specific surface area to accommodate and 11098 mAh g -1 at 1 A g -1 ), approximately 100% coulombic efficiency, and remarkably cycling performance (260 cycles at 400 mA g -1 ). As shown in Figure 16(i), abundant…”

Nanoporous Composites of CoOx Quantum Dots and ZIF-Derived Carbon as High-Performance Anodes for Lithium-Ion Batteries

“… 12 , 13 For example, Wang et al fabricated ultrathin carbon nanosheets by calcining ZIF-8 in an argon atmosphere. 14 The MOF-derived carbonaceous materials have flourished as advanced electrode materials in the energy storage field. 15 − 17 …”