Effects of multi-dopants (Zn and Ho) in stabilizing spinel structure for cathode materials in lithium rechargeable batteries—Novel chelated sol

Thirunakaran, R., Kim, T., & Yoon, W.-S. (2016). Effects of multi-dopants (Zn and Ho) in stabilizing spinel structure for cathode materials in lithium rechargeable batteries—Novel chelated sol–gel synthesis. Particuology, 24, 87-95. https://doi.org/10.1016/j.partic.2015.03.003

Effects of multi-dopants (Zn and Ho) in stabilizing spinel structure for cathode materials in lithium rechargeable batteries—Novel chelated sol–gel synthesis

R. Thirunakaran ^a *, Taewhan Kim ^b, Won-Sub Yoon ^b *

a CSIR—Central Electrochemical Research Institute, Karaikudi 630 006, Tamil Nadu, India
b Department of Energy Science, Sungkyunkwan University, Suwon 440-746, South Korea

10.1016/j.partic.2015.03.003

Volume 24, February 2016, Pages 87-95

Received 5 December 2014, Revised 7 March 2015, Accepted 10 March 2015, Available online 8 July 2015, Version of Record 21 January 2016.

E-mail: rthirunakaran@yahoo.com; wsyoon@skku.edu

Highlights

• Multi-doped pristine spinels used as cathode materials were synthesized via sol–gel method.

• The synthesized samples exhibited high degrees of crystallinity and good phase purity.

• LiZn_0.10Ho_0.10Mn_1.80O₄ was an appropriate candidate for use in lithium-ion rechargeable batteries.

Abstract

Multi-doped spinels, namely LiMn₂O₄ and LiZn_xHo_yMn₂_−x−yO₄ (x = 0.10–0.18; y = 0.02–0.10), for use as cathode materials for lithium-ion rechargeable batteries were synthesized via sol–gel method, using lauric acid as the chelating agent, to obtain micron-sized particles. The physical properties of the synthesized samples were investigated using differential thermal analysis, Fourier-transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy, energy-dispersive X-ray analysis, and electrochemical methods. XRD showed that LiMn₂O₄and LiZn_xHoyMn_2−x−yO₄ have high degrees of crystallinity and good phase purities. The SEM images of LiMn₂O₄ showed an ice-cube morphology with particles of size 1 μm. Charge–discharge studies showed that undoped LiMn₂O₄ delivered the discharge capacity of 124 mA h/g with coulombic efficiency of 95% during the first cycle, whereas doped spinels delivered discharge capacities of 125, 120, and 127 mA h/g in the first cycle with coulombic efficiencies of 96%, 91%, and 91%, respectively.

Graphical abstract

Keywords

Holmium; Zinc; Lauric acid; Sol–gel; Spinel cathode; Lithium-ion battery

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