Structural Evolution of Layered Manganese Oxysulfides during Reversible Electrochemical Lithium Insertion and Copper Extrusion
- Univ. of Cambridge (United Kingdom). Dept. of Chemistry
- State Univ. of New York (SUNY), Stony Brook, NY (United States). Dept. of Chemistry
- Univ. of Oxford (United Kingdom). Inorganic Chemistry Lab. Dept. of Chemistry
- Univ. of Oxford (United Kingdom). Inorganic Chemistry Lab. Dept. of Chemistry
- Univ. of Oxford (United Kingdom). Inorganic Chemistry Lab. Dept. of Chemistry; State Univ. of New York (SUNY), Stony Brook, NY (United States). Dept. of Chemistry
The electrochemical lithiation and delithiation of the layered oxysulfide Sr2MnO2Cu4-δS3 has been investigated by using a combination of in situ powder X-ray diffraction and ex situ neutron powder diffraction, X-ray absorption and 7Li NMR spectroscopy, together with a range of electrochemical experiments. Sr2MnO2Cu4-δS3 consists of [Sr2MnO2] perovskite-type cationic layers alternating with highly defective antifluorite-type [Cu4-δS3] (δ ≈ 0.5) anionic layers. It undergoes a combined displacement/intercalation (CDI) mechanism on reaction with Li, where the inserted Li replaces Cu, forming Li4S3 slabs and Cu+ is reduced and extruded as metallic particles. For the initial 2-3% of the first discharge process, the vacant sites in the sulfide layer are filled by Li; Cu extrusion then accompanies further insertion of Li. Mn2.5+ is reduced to Mn2+ during the first half of the discharge. The overall charging process involves the removal of Li and re-insertion of Cu into the sulfide layers with re-oxidation of Mn2+ to Mn2.5+. However, due to the different diffusivities of Li and Cu, the processes operating on charge are quite different from those operating during the first discharge: charging to 2.75 V results in the removal of most of the Li, little reinsertion of Cu, and good capacity retention. A charge to 3.75 V is required to fully reinsert Cu, which results in significant changes to the sulfide sublattice during the following discharge and poor capacity retention. This detailed structure-property investigation will promote the design of new functional electrodes with improved device performance.
- Research Organization:
- State Univ. of New York (SUNY), Stony Brook, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division
- Grant/Contract Number:
- SC0001294
- OSTI ID:
- 1816689
- Journal Information:
- Chemistry of Materials, Vol. 33, Issue 11; ISSN 0897-4756
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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