High‐Performance Li‐CO2 Batteries Based on Metal‐Free Carbon Quantum Dot/Holey Graphene Composite Catalysts

By Yachao Jin, Chuangang Hu, Quanbin Dai, Ying Xiao, Yi Lin, J. Connell, Fuyi Chen, L. Dai. Advanced Functional Materials, 2018

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Li‐CO2 batteries have attracted ever increasing attention due to their high energy and power densities. However, Li2CO3 formed during the discharge process is difficult to decompose, leading to a large charge overpotential and poor cyclability. Thus, high‐performance and low‐cost catalysts that can be integrated into the electrode architecture are urgently needed for the development of practical Li‐CO2 batteries with a low overpotential and long cyclability. Herein, a high‐performance composite catalyst is reported based on carbon quantum dots supported by holey graphene (CQD/hG), which, when used as the cathodic catalyst in a Li‐CO2 battery, can support the fast formation and decomposition of Li2CO3 in organic electrolytes and achieve an overpotential as low as 1.02 V (Li/Li+) at current density of 0.1 A g−1. The discharge capacity of this Li‐CO2 battery is 12300 mAh g−1 under the current density of 0.5 A g−1, showing an excellent long‐term stability with up to 235 cycles even at a high current density of 1 A g−1. The observed superb battery performance is attributable to synergistic effects that the CQD/hG composite architecture provides a high catalytic activity of the defect‐rich CQDs and fast electron/electrolyte transport through the conducting holey graphene sheets.

Subfields: Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials

View Paper: https://www.semanticscholar.org/paper/037a55f753ea12d3a086e544e6ef3067082773a9