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The critical role of the crystallite size in nanostructured Li4Ti5O12 anodes for lithium ion batteries

DOI: 10.1021/acsami.8b05057 DOI Help

Authors: Junpei Yue (Justus-Liebig-University Giessen) , Felix M. Badaczewski (Justus-Liebig-University Giessen) , Pascal Voepel (Justus-Liebig-University Giessen) , Thomas LeichtweiƟ (Center for Materials Research (LaMa)) , Doreen Mollenhauer (Justus-Liebig-University Giessen; Center for Materials Research (LaMa)) , Wolfgang G. Zeier (Justus-Liebig-University Giessen) , Bernd M. Smarsly (Justus-Liebig-University Giessen; Center for Materials Research (LaMa))
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Applied Materials & Interfaces

State: Published (Approved)
Published: June 2018
Diamond Proposal Number(s): 13560

Abstract: Lithium titanate Li4Ti5O12 (LTO) is regarded as a promising alternative to carbon-based anodes in lithium-ion batteries. Despite its stable structural framework, LTO exhibits disadvantages such as the sluggish lithium-ion diffusion and poor electronic conductivity. In order to modify the performance of LTO as an anode material, nanosizing constitutes a promising approach, and the impact is studied here by systematical experimental approach. Phase-pure polycrystalline LTO nanoparticles (NPs) with high crystallinity and crystallite sizes ranging from 4 to 12 nm are prepared by an optimized solvothermal protocol and characterized by several state-of-the-art technologies including HRTEM, XRD, PDF (pair distribution function) analysis, Raman spectroscopy and XPS. Through a wide array of electrochemical analyses, including charge/discharge profiles, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), a crystallite size of approx. 7 nm is identified as optimum particle size. Such NPs exhibit as good reversible capacity as the ones with larger crystallite sizes, but a more pronounced interfacial charge storage. By decreasing the crystallite size to about 4 nm the interfacial charge storage increases remarkably, however resulting in a loss of reversible capacity. An in-depth structural characterization using the PDF obtained from synchrotron XRD data indicates an enrichment in Ti for NPs with the small crystallite sizes, and this Ti-rich structure enables a higher Li storage. The electrochemical characterization confirms this result and furthermore points to a plausible reason why a higher Li-storage in very small nanoparticles (4 nm) results in a loss in the reversible capacity.

Journal Keywords: Li4Ti5O12; Nanoparticles; Mesoporous Fiber; Mesoporous Film; Size Effects; Interfacial Charge Storage; Pair Distribution Function

Diamond Keywords: Batteries; Lithium-ion; Electric Vehicles

Subject Areas: Chemistry, Energy, Materials

Instruments: I15-Extreme Conditions

Added On: 11/06/2018 09:13

Discipline Tags:

Energy Storage Energy Physical Chemistry Energy Materials Chemistry Materials Science Nanoscience/Nanotechnology

Technical Tags:

Scattering Pair Distribution Function (PDF)