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Rechargeable K‐CO 2 Batteries with a KSn Anode and a Carboxyl‐Containing Carbon Nanotube Cathode Catalyst
Author(s) -
Lu Yong,
Cai Yichao,
Zhang Qiu,
Ni Youxuan,
Zhang Kai,
Chen Jun
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202016576
Subject(s) - overpotential , anode , cathode , catalysis , carbon nanotube , battery (electricity) , materials science , redox , chemical engineering , decomposition , carbon fibers , electrochemistry , nanotechnology , chemistry , inorganic chemistry , electrode , composite material , organic chemistry , composite number , thermodynamics , power (physics) , physics , engineering
Metal K‐CO 2 batteries suffer from large polarization and safety hazards, which mainly result from the difficult decomposition of K 2 CO 3 and dendrite growth. Moreover, the battery redox mechanism remains not fully understood. Here we report K‐CO 2 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 CO 2 ⇄ 2 K 2 CO 3 + C + 4 Sn. Compared with K metal, the less active and dendrite‐free KSn anode effectively enhances the safety and stability of CO 2 batteries. More importantly, the strong electrostatic interaction between MWCNTs‐COOH and K 2 CO 3 weakens the C=O bond in K 2 CO 3 and thus facilitates K 2 CO 3 decomposition. As a result, the K‐CO 2 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 CO 2 ‐based batteries.