Enhancing the Electrochemical Performance of Sodium‐Ion Batteries by Building Optimized NiS2/NiSe2 Heterostructures. Issue 45 (7th October 2021)

• Record Type: Journal Article
• Authors: He, Shu‐Ang; Cui, Zhe; Liu, Qian; He, Guanjie; Brett, Dan J. L.; Luo, Wei; Zou, Rujia; Zhu, Meifang
• Is Part Of: Small. Volume 17:Issue 45(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-07
• Subjects: cavity structures -- NiS 1.23Se 0.77 nanosheets -- sodium‐ion batteries -- sulfide/selenide heterostructures -- ultrahigh initial coulombic efficiency; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202104186
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: NiS1.23 Se0.77 nanosheets closely attached to the internal surface of hollow mesoporous carbon sphere (HMCS) to form a NiS1.23 Se0.77 nanosheets embedded in HMCS (NSSNs@HMCS) composite as the anode of sodium ion batteries (SIBs) is reported by a facile synthesis route. The anode exhibits a superior reversible capacity (520 mAh g −1 at 0.1 A g −1 ), impressive coulombic efficiency (CE) of up to 95.3%, a high rate capacity (353 mAh g −1 at 5.0 A g −1 ), excellent capacity retention at high current density (95.6%), and high initial coulombic efficiency (ICE) (95.1%). Firstly, the highest ICE for NiS2 /NiSe2 ‐based anode can be ascribed to ultrathin layered structure of NiS1.23 Se0.77 nanosheet and highly efficient electron transfer between the active material and HMCS. Secondly, the optimized NiS2 /NiSe2 heterostructure at the nanoscale of the inside HMCS is formed after the first discharge/charge cycles, which can provide rich heterojunction interfaces/boundaries of sulfide/selenides to offer faster Na + pathways, decrease the Na + diffusion barriers, increase electronic conductivity, and limit the dissolution of polysulfides or polyselenides in the electrolyte. Finally, the hollow structure of the HMCS accommodates the volume expansion, prevents the pulverization and aggregation issues of composite materials, which can also promote outstanding electrochemical performance. Abstract : The optimized NiS2 /NiSe2 heterostructure at the nanoscale on the inner surface of a hollow mesoporous carbon sphere is formed after the first discharge/charge cycles, which can provide rich heterojunction interfaces/boundaries of sulfide/selenides to offer faster Na + pathways, decrease the Na + diffusion barriers, increase electronic conductivity, and limit the dissolution of polysulfides or polyselenides in the electrolyte.