Enhancing the Electrochemical Properties of Ti-Doped LiMn₂O₄ Spinel Cathode Materials Using a One-Step Hydrothermal Method

Abstract

In this study, LiMn 2– x Ti x O 4 cathode materials were synthesized by a simple one-step hydrothermal method, and the effects of Ti doping on the sample structure and electrochemical properties were examined. The results indicated that Ti doping did not affect the spinel structure of LiMn 2 O 4 , and no other hybrid phases were produced. Furthermore, appropriate doping with Ti improved the particle uniformity of the samples. The electrochemical performance results showed that LiMn 1.97 Ti 0.03 O 4 exhibited much better cycling performance than the undoped sample. The discharge capacity of LiMn 1.97 Ti 0.03 O 4 reached 136 mAh g –1 at 25 °C at 0.2C, and the specific capacity reached 106.2 mAh g –1 after 300 cycles, with a capacity retention rate of 78.09%. Additionally, the specific capacity of LiMn 1.97 Ti 0.03 O 4 was 102.3 mAh g –1 after 100 cycles at 55 °C, with a capacity retention rate of 75.44%. The Ti-doped samples thus exhibited an impressive high-rate performance. The discharge capacity of LiMn 2 O 4 was only 31.3 mAh g –1 at 10C, while the discharge-specific capacity of LiMn 1.97 Ti 0.03 O 4 reached 73.4 mAh g –1 . Furthermore, to assess the higher Li + diffusion coefficient and lower internal resistance of the Ti-doped samples, cyclic voltammetry and impedance spectra data were obtained. Our results showed that Ti doping enhanced the crystal structure of LiMn 2 O 4 and improved Li + diffusion, resulting in significant improvements in the cycling and rate performance of Ti-doped samples.

Ethanothermal Synthesis of Octahedral-Shaped Doped Mn2O3 Single Crystals as a Precursor for LiMn2O4 Spinel Cathodes in Lithium-Ion Batteries

“…To explore the effect of Al and Ti codoping in the spinel structure, undoped, Al-doped, Ti-doped, and Al and Ti codoped LMO samples were evaluated in lithium-ion cells. It has been reported that Al-doping − or Ti doping − in LMO spinel is beneficial for overall cell performance while losing some capacity due to the electrochemical inactivity of Al and Ti dopants. , In both cases, however, the doping element helps to overcome the Mn dissolution problem during cycling by perturbing the long-range direct Mn–Mn interaction through the shared edges . Despite the previous studies on elemental substitution, the codoping of LMO spinel with a small amount of both Al and Ti has not yet been investigated systematically. , Accordingly, the electrochemical characteristics of the Al and Ti codoped LMO cathodes are compared with the singly doped and undoped LMO cathodes.…”

Nanocubes of Mo6S8 Chevrel phase as active electrode material for aqueous lithium-ion batteries

“…This phenomenon is ascribed to the low conductivity of LiMn 2 O 4 and the Jahn-Teller distortion arising from the thermodynamic instability of the spinel lattice. 9,45,46 In order to investigate the intercalation of Li + ions into Mo 6 S 8 nanocubes, ex situ post-mortem XRD and XPS measurements were performed on cycled electrodes. The full cell was charged and discharged at a 0.2 C rate and the negative electrode was recovered from the cell and washed thoroughly with water before the measurements.…”

“…This phenomenon is ascribed to the low conductivity of LiMn 2 O 4 and the Jahn–Teller distortion arising from the thermodynamic instability of the spinel lattice. 9,45,46…”

“…The observed increase in the charge transfer value (as qualitatively estimated by the diameter of the depressed semicircle observed at the intermediate frequency range) may be attributed to the capacity fade of the positive electrode (LiMn 2 O 4 ) during cycling, as has been recently reported for systems using 21 m LiTFSI electrolytes. This phenomenon is ascribed to the low conductivity of LiMn 2 O 4 and the Jahn-Teller distortion arising from the thermodynamic instability of the spinel lattice9,45,46 .In order to investigate the intercalation of Li + ions into Mo 6 S 8 nanocubes, ex-situ post-mortem XRD and XPS measurements were performed on cycled electrodes. The full cell was charged and discharged at a 0.2C rate and the negative electrode was recovered from the cell and washed thoroughly with water before the measurements.…”

Sol‐gel route synthesis of high energy density Li [Li0.2Ni0.3Mn0.7] O2 cathode with controlled structure, morphology and enhanced electrochemical performance

“…In addition, the inclusion of suitable metal dopants were able to eliminate the impurity phases. Facile hydrothermal method suggested by Zhang et al achieved a highest initial discharge capacity (352.8 mAhg −1 ) with layered material and faded drastically after 50 cycles with a capacity retention of 75.5% 8‐11 …”