Rechargeable K‐CO2 Batteries with a KSn Anode and a Carboxyl‐Containing Carbon Nanotube Cathode Catalyst

Metal K‐CO2 batteries suffer from large polarization and safety hazards, which mainly result from the difficult decomposition of K2CO3 and dendrite growth. Moreover, the battery redox mechanism remains not fully understood. Here we report K‐CO2 batteries with KSn alloy as the anode and carboxyl‐cont...

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Bibliographic Details
Published in:Angewandte Chemie 2021-04, Vol.133 (17), p.9626-9631
Main Authors: Lu, Yong, Cai, Yichao, Zhang, Qiu, Ni, Youxuan, Zhang, Kai, Chen, Jun
Format: Article
Language:English
Subjects:
Anode effect
batteries
Carbon dioxide
carbon nanotubes
Catalysts
Cathodes
Cathodic polarization
Chemistry
Decomposition
Dendrites
Dendritic structure
Electrode polarization
electrostatic interactions
Electrostatic properties
KSn alloy
Multi wall carbon nanotubes
Nanotechnology
Nanotubes
Potassium carbonate
Rechargeable batteries
Safety
Stability
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Summary:Metal K‐CO2 batteries suffer from large polarization and safety hazards, which mainly result from the difficult decomposition of K2CO3 and dendrite growth. Moreover, the battery redox mechanism remains not fully understood. Here we report K‐CO2 batteries with KSn alloy as the anode and carboxyl‐containing multi‐walled carbon nanotubes (MWCNTs‐COOH) as the cathode catalyst, proving the redox mechanism to be 4 KSn + 3 CO2 ⇄ 2 K2CO3 + C + 4 Sn. Compared with K metal, the less active and dendrite‐free KSn anode effectively enhances the safety and stability of CO2 batteries. More importantly, the strong electrostatic interaction between MWCNTs‐COOH and K2CO3 weakens the C=O bond in K2CO3 and thus facilitates K2CO3 decomposition. As a result, the K‐CO2 batteries show excellent cycling stability (an overpotential increase of 0.89 V after 400 cycles) and good rate performance (up to 2000 mA g−1). This work paves a way to develop highly stable and safe CO2‐based batteries. Rechargeable K‐CO2 batteries successfully fabricated with a KSn anode and a carboxyl‐containing carbon nanotube cathode catalyst exhibit superior cycling stability and good rate performance because of the strong electrostatic interaction between the cathode catalyst and K2CO3, along with a dendrite‐free anode with high stability. Moreover, the redox mechanism has been verified as 4 KSn + 3 CO2 ⇄ 2 K2CO3 + C + 4 Sn.
ISSN:0044-8249
1521-3757
DOI:10.1002/ange.202016576