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High‐Performance Li‐CO 2 Batteries Based on Metal‐Free Carbon Quantum Dot/Holey Graphene Composite Catalysts
Author(s) -
Jin Yachao,
Hu Chuangang,
Dai Quanbin,
Xiao Ying,
Lin Yi,
Connell John W.,
Chen Fuyi,
Dai Liming
Publication year - 2018
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201804630
Subject(s) - overpotential , materials science , graphene , battery (electricity) , electrolyte , catalysis , composite number , current density , carbon fibers , quantum dot , nanotechnology , chemical engineering , electrode , composite material , electrochemistry , power (physics) , chemistry , organic chemistry , physics , quantum mechanics , engineering
Li‐CO 2 batteries have attracted ever increasing attention due to their high energy and power densities. However, Li 2 CO 3 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‐CO 2 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‐CO 2 battery, can support the fast formation and decomposition of Li 2 CO 3 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‐CO 2 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.