Er-Doped LiNi0.5Mn1.5O4 Cathode Material with Enhanced Cycling Stability for Lithium-Ion Batteries

Abstract

The Er-doped LiNi0.5Mn1.5O4 (LiNi0.495Mn1.495Er0.01O4) sample was successfully prepared by citric acid-assisted sol-gel method with erbium oxide as an erbium source for the first time. Compared with the undoped sample, the Er-doped LiNi0.5Mn1.5O4 sample maintained the basic spinel structure, suggesting that the substitution of Er3+ ions for partial nickel and manganese ions did not change the intrinsic structure of LiNi0.5Mn1.5O4. Moreover, the Er-doped LiNi0.5Mn1.5O4 sample showed better size distribution and regular octahedral morphology. Electrochemical measurements indicated that the Er-doping could have a positive impact on the electrochemical properties. When cycled at 0.5 C, the Er-doped LiNi0.5Mn1.5O4 sample exhibited an initial discharge capacity of 120.6 mAh·g−1, and the capacity retention of this sample reached up to 92.9% after 100 cycles. As the charge/discharge rate restored from 2.0 C to 0.2 C, the discharge capacity of this sample still exhibited 123.7 mAh·g−1 with excellent recovery rate. Since the bonding energy of Er-O (615 kJ·mol−1) was higher than that of Mn-O (402 kJ·mol −1) and Ni-O (392 kJ·mol−1), these outstanding performance could be attributed to the increased structure stability as well as the reduced aggregation behavior and small charge transfer resistance of the Er-doped LiNi0.5Mn1.5O4.

Utilizing the Intrinsic Thermal Instability of Swedenborgite Structured YBaCo4O7+δ as an Opportunity for Material Engineering in Lithium-Ion Batteries by Er and Ga Co-Doping Processes

“…Meanwhile, there are a few reports adopting Er or Ga as dopants for cathode-active materials in LIBs. While Er-doped LiFePO 4 and LiNi 0.5 Mn 1.5 O 4 showed improved cycling stability [23,24], Ga-doped layered LiN 0.6 Co 0.2 Mn 0.2 O 2 presented enhanced electrochemical performance and thermal stability, which is in line with the Manthiram group's result based on the YBC material related to the improved phase stability at high temperatures [21,25].…”

Improved Electrochemical Properties of LiMn2O4-Based Cathode Material Co-Modified by Mg-Doping and Octahedral Morphology

“…For the LiMn 1.95 Mg 0.05 O 4 sample obtained from Mn 3 O 4 octahedra, the characteristic diffraction peaks were indexed to the spinel LiMn 2 O 4 . Moreover, the corresponding peak intensities are stronger than that of the LiMn 2 O 4 and LiMn 1.95 Mg 0.05 O 4 samples prepared from electrolytic manganese dioxide, suggesting the good crystalline quality of the octahedral LiMn 1.95 Mg 0.05 O 4 sample [9,34]. Table 1 lists the related crystal parameters of these three samples.…”

Role of Mn Content on the Electrochemical Properties of Nickel-Rich Layered LiNi0.8–xCo0.1Mn0.1+xO2 (0.0 ≤ x ≤ 0.08) Cathodes for Lithium-Ion Batteries

“…To date, lithium-rich layered oxides and nickel-rich layered oxides have been intensively investigated as high-energy density cathodes. Albeit the high discharge capacity (∼250 mA h g –1 ), significant challenges including voltage fade during cycling and limited cycle life exist with lithium-rich layered oxides. − Similarly, Ni-rich layered LiNi x Co y Mn z O 2 (NCM) cathodes with x > 0.60 and involving both the Ni 2+/3+ and Ni 3+/4+ couples offer capacities of 200–220 mA h g –1 but require high charge cutoff voltages of 4.5 V or above. − …”