CuO Nanoplates for High‐Performance Potassium‐Ion Batteries

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2019-09, Vol.15 (36), p.e1901775-n/a
• Main Authors: Cao, Kangzhe, Liu, Huiqiao, Li, Wangyang, Han, Qingqing, Zhang, Zhang, Huang, Kejing, Jing, Qiangshan, Jiao, Lifang
• Format: Article
• Language: English
• Subjects: anode; Anodes; Conversion; Copper; Copper oxides; CuO; Electrode materials; Electrodes; high performance; Ion diffusion; K‐ion storage behavior; Lithium-ion batteries; Low cost; Nanoparticles; Nanotechnology; Potassium; potassium‐ion batteries; Rechargeable batteries; Thickness
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201901775

Potassium‐ion batteries (KIBs) are promising alternatives to lithium‐ion batteries because of the abundance and low cost of K. However, an important challenge faced by KIBs is the search for high‐capacity materials that can hold large‐diameter K ions. Herein, copper oxide (CuO) nanoplates are synthesized as high‐performance anode materials for KIBs. CuO nanoplates with a thickness of ≈20 nm afford a large electrode–electrolyte contact interface and short K+ ion diffusion distance. As a consequence, a reversible capacity of 342.5 mAh g−1 is delivered by the as‐prepared CuO nanoplate electrode at 0.2 A g−1. Even after 100 cycles at a high current density of 1.0 A g−1, the capacity of the electrode remains over 206 mAh g−1, which is among the best values for KIB anodes reported in the literature. Moreover, a conversion reaction occurs at the CuO anode. Cu nanoparticles form during the first potassiation process and reoxidize to Cu2O during the depotassiation process. Thereafter, the conversion reaction proceeds between the as‐formed Cu2O and Cu, yielding a reversible theoretical capacity of 374 mAh g−1. Considering their low cost, easy preparation, and environmental benignity, CuO nanoplates are promising KIB anode materials. Copper oxide (CuO) nanoplates with a thickness of about 20 nm are synthesized for potassium‐ion battery anodes. A reversible capacity of 342.5 mAh g−1 is delivered by the as‐prepared CuO nanoplate electrode at 0.2 A g−1, and its potassium‐ion storage behavior based on a conversion reaction mechanism is systematically studied for the first time.