Rechargeable Li-CO2 Batteries with Graphdiyne as Efficient Metal-Free Cathode Catalysts

A rechargeable Li-CO2 battery is one of the promising power sources for utilizing the greenhouse gas CO2 in a sustainable approach. However, highly efficient catalysts for reversible formation/decomposition of insulating discharge product, Li2CO3, are the main challenge, which can boost the cycle stability. Herein, 2D single-atom-thick graphdiyne (GDY) with abundant acetylenic bond sites is prepared by a bottom-up cross-coupling reaction strategy and used as metal-free catalysts for reversible Li-CO2 batteries. The prepared GDY has a rich diacetylenic unit and atomic-level in-plane pores in the network, which can chemically adsorb the CO2 molecules and easily promote the Li+ diffusion and thereby resulting in uniform nucleation and reversible formation/decomposition of the discharge product. The GDY hybrid cathodes show a small overpotential gap of 1.4 V at a current density of 50 mA center dot g(-1), a high full discharge capacity of 18 416 mAh center dot g(-1) at 100 mA center dot g(-1), and outstanding long-term stability of 158 cycles at 400 mA center dot g(-1) with a curtailing capacity of 1000 mAh center dot g(-1). Furthermore, a flexible belt-shaped Li-CO2 battery is fabricated as a proof of concept with a high gravimetric energy density of 165.5 Wh center dot kg(-1) (based on the mass of the whole device) as well as excellent mechanical flexibility.

Automated summary

By preparing GDY catalyst, efficient and stable cycling of rechargeable Li-CO2 batteries has been achieved, potentially improving battery performance and long-term stability.