Defect engineering via the F-doping of β-MnO2 cathode to design hierarchical spheres of interlaced nanosheets for superior high-rate aqueous zinc ion batteries

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 9; no. 32; pp. 17211 - 17222
• Main Authors: Kim, Seoyeong, Koo, Bon-Ryul, Yong-Ryun Jo, Ha-Rim An, Young-Geun, Lee, Huang, Chun, An, Geon-Hyoung
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 28.08.2021
• Subjects: Cathodes; Chemical reactions; Design defects; Doping; Electrical conductivity; Electrical resistivity; Electrochemical analysis; Electrochemistry; Electrode materials; Energy storage; Flammability; Fluorine; Flux density; Insertion; Kinetics; Lattice vacancies; Lithium; Manganese dioxide; Nanosheets; Rechargeable batteries; Structural hierarchy; Zinc
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d1ta04051k

The rechargeable aqueous Zn ion battery (ZIB) is a promising candidate for next-generation energy storage technology due to its low cost, low flammability, inherent safety, and high theoretical capacity. Nevertheless, the β-MnO2 cathode material continues to be limited by inactive ion insertion and transport kinetics due to a relatively narrow tunneling pathway, thus leading to low capacity and rate capabilities. Hence, to achieve a high-performance ZIB, the presence of lattice and defect structures in the β-MnO2 is required to promote the electrochemical reactions. Herein, for the first time, a β-MnO2 cathode with a hierarchical structure consisting of spheres of interlaced nanosheets is introduced via efficient defect engineering using fluorine (F)-doping and oxygen vacancies, thus leading to improved ion insertion and transport kinetics along with an enhanced electrical conductivity. The ZIB is shown to exhibit a high energy density (288 W h kg−1 at a power density of 90 W kg−1), a superior high-rate performance (energy density of 158 W h kg−1 at a power density of 1800 W kg−1), and a capacity retention (85% after up to 150 cycles). These results highlight the potential of defect-engineered cathode materials for the enhanced electrochemical performance of rechargeable aqueous batteries.