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Superior sodium storage properties in the anode material NiCr2S4 for sodium-ion batteries: An X-ray diffraction, pair distribution function, and X-ray absorption study reveals a conversion mechanism via nickel extrusion

DOI: 10.1002/adma.202101576 DOI Help

Authors: Felix Hartmann (Christian-Albrechts University of Kiel) , Martin Etter (Deutsches Elektronen-Synchrotron (DESY)) , Giannantonio Cibin (Diamond Light Source) , Lina Liers (Christian-Albrechts University of Kiel) , Huayna Terraschke (Christian-Albrechts University of Kiel) , Wolfgang Bensch (Christian-Albrechts University of Kiel)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Advanced Materials , VOL 7

State: Published (Approved)
Published: September 2021
Diamond Proposal Number(s): 20060

Open Access Open Access

Abstract: The pseudo-layered sulfide NiCr2S4 exhibits outstanding electrochemical performance as anode material in sodium-ion batteries (SIBs). The Na storage mechanism is investigated by synchrotron-based X-ray scattering and absorption techniques as well as by electrochemical measurements. A very high reversible capacity in the 500th cycle of 489 mAh gāˆ’1 is observed at 2.0 A gāˆ’1 in the potential window 3.0ā€“0.1 V. Full discharge includes irreversible generation of Ni0 and Cr0 nanoparticles embedded in nanocrystalline Na2S yielding shortened diffusion lengths and predominantly surface-controlled charge storage. During charge, Ni0 and Cr0 are oxidized, Na2S is consumed, and amorphous Ni and Cr sulfides are formed. Limiting the potential window to 3.0ā€“0.3 V an unusual nickel extrusion sodium insertion mechanism occurs: Ni2+ is reduced to nanosized Ni0 domains, expelled from the host lattice, and is replaced by Na+ cations to form O3-type like NaCrS2. Surprisingly, the discharge and charge processes comprise Na+ shuttling between highly crystalline NiCr2S4 and NaCrS2 enabling a superior long-term stability for 3000 cycles. The results not only provide valuable insights for the electrochemistry of conversion materials but also extend the scope of layered electrode materials considering the reversible nickel extrusion sodium insertion reaction as new concept for SIBs.

Diamond Keywords: Batteries; Sodium-ion

Subject Areas: Materials, Chemistry

Instruments: B18-Core EXAFS

Other Facilities: P02.1 at PETRA III

Added On: 09/09/2021 13:26


Discipline Tags:

Energy Storage Energy Physical Chemistry Energy Materials Chemistry Materials Science

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS)