Boosted Reaction Kinetics of Li-Co2 Batteries by Atomic Layer Deposited Mo2n on Hydrogen Substituted Graphdiyne

Li-CO2 batteries are considered as promising power systems to realize high-density energy storage and effective CO2 fixation. However, the sluggish kinetics of the decomposition of CO2 reduction product Li2CO3 in the batteries causes high overpotential and poor rechargeability. Herein, carbon/metal nitride composite catalysts comprised of hydrogen substituted graphdiyne (HsGDY) with atomic layer deposited Mo2N are fabricated. The homogeneously atomic deposited Mo2N on HsGDY catalysts significantly accelerate the reaction kinetics of CO2 redox reaction and Li2CO3 decomposition in Li-CO2 batteries. The fabricated Li-CO2 batteries deliver an ultrahigh full discharge capacity of 37416 mAh·g-1 at a large current density of 0.1 A·g -1, and show a high median discharge voltage of 2.82 V and low charge voltage of 3.95 V with a small voltage gap of 1.13 V. Furthermore, the battery also shows long-term stability of 1200 h (61 cycles) at 0.1 A·g-1 with limiting the capacity of 1000 mAh·g-1, and outstanding rate capability and cyclability at up to 2.0 A·g-1 with a well-maintained median discharge voltage of 2.67 V and charge voltage of 4.24 V. This work sheds light on designing and fabricating efficient and durable catalysts for high-performance Li-CO2 batteries.