Self-Templated Formation of P2-type K0.6CoO2 Microspheres for High Reversible Potassium-Ion Batteries

• Published in: Nano letters Vol. 18; no. 2; pp. 1522 - 1529
• Main Authors: Deng, Tao, Fan, Xiulin, Luo, Chao, Chen, Ji, Chen, Long, Hou, Singyuk, Eidson, Nico, Zhou, Xiuquan, Wang, Chunsheng
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14.02.2018
• Subjects: bio-inspired; Cathode material; charge transport; defects; ENERGY STORAGE; energy storage (including batteries and capacitors); high reversibility; K0.6CoO2; layered metal oxides; MATERIALS SCIENCE; potassium-ion battery; synthesis (novel materials); synthesis (scalable processing); synthesis (self-assembly); Cathode material; high reversibility; layered metal oxides; potassium-ion battery; K0.6CoO2
• ISSN: 1530-6984; 1530-6992; 1530-6992
• DOI: 10.1021/acs.nanolett.7b05324

Layered metal oxides have been widely used as the best cathode materials for commercial lithium-ion batteries and are being intensively explored for sodium-ion batteries. However, their application to potassium-ion batteries (PIBs) is hampered because of the poor cycling stability and low rate capability due to the larger ionic size of K+ than of Li+ or Na+. Herein, a facile self-templated strategy was used to synthesize unique P2-type K0.6CoO2 microspheres that consist of aggregated primary nanoplates as PIB cathodes. The unique K0.6CoO2 microspheres with aggregated structure significantly enhanced the kinetics of the K+ intercalation/deintercation and also minimized the parasitic reactions between the electrolyte and K0.6CoO2. The P2-K0.6CoO2 microspheres demonstrated a high reversible capacity of 82 mAh g–1 at 10 mA g–1, high rate capability of 65 mAh g–1 at 100 mA g–1, and long cycle life (87% capacity retention over 300 cycles). The high reversibility of the P2-K0.6CoO2 full cell paired with a hard carbon anode further demonstrated the feasibility of PIBs. This work not only successfully demonstrates exceptional performance of P2-type K0.6CoO2 cathodes and microspheres K0.6CoO2∥hard carbon full cells, but also provides new insights into the exploration of other layered metal oxides for PIBs.