Hollandite‐Type VO1.75(OH)0.5: Effective Sodium Storage for High‐Performance Sodium‐Ion Batteries. Issue 22 (24th April 2019)

• Record Type: Journal Article
• Authors: Jo, Jae Hyeon; Choi, Ji Ung; Cho, Min Kyung; Aniskevich, Yauhen; Kim, Hyungsub; Ragoisha, Genady; Streltsov, Eugene; Kim, Jongsoon; Myung, Seung‐Taek
• Is Part Of: Advanced energy materials. Volume 9:Issue 22(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-04-24
• Subjects: first‐principles calculations -- Hollandite -- intercalation -- sodium batteries -- vanadium oxyhydroxide; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201900603
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: Nanosized hollandite‐type VO1.75 (OH)0.5 is introduced as a novel cathode material for Na‐ion batteries. Structural investigation based on X‐ray diffraction and Rietveld refinement suggests the presence of numerous vacant sites for Na + intercalation in the VO1.75 (OH)0.5 structure. All of the possible Na + sites and tunnel‐type Na + diffusion pathways along the c ‐axis are confirmed by bond‐valence‐sum analyses. The nanosized hollandite‐type VO1.75 (OH)0.5 delivers an unexpectedly high specific capacity of ≈351 mAh g −1 at 15.5 mA g −1 in the voltage range of 1.0–3.7 V (vs Na + /Na), which agrees well with the results predicted by first‐principles calculations. In addition, combined studies using first‐principles calculations and several experimental techniques including in situ operando X‐ray diffraction and ex situ X‐ray absorption spectroscopy confirm that the nanosized hollandite‐type VO1.75 (OH)0.5 undergoes a single‐phase reaction with a capacity retention of 71% over 200 cycles. Furthermore, the open structure and nanosized particles of hollandite‐type VO1.75 (OH)0.5 contribute to its excellent power capability with 56% of the capacity measured at 0.05 C being delivered at 7 C. Abstract : The possibility of using Na x VO1.75 (OH)0.5 as a new outstanding cathode material for sodium‐ion batteries is reported. Combined studies using first‐principles calculations and various experimental techniques reveal that large tunnels in the structure enable the insertion of large sodium ions followed by a single‐phase reaction with the V 4+/3+ redox pair.