Enhanced Structural, Electrochemical, and Electrode Kinetic Properties of Na_0.5Ni_0.2Mg_0.1Mn_0.7O₂ Material for Sodium-Ion Battery Applications

Abstract

The hybrid P3/P2-structured Na 0.5 Ni 0.3 Mn 0.7 O 2 as a cathode material for sodium-ion batteries (SIBs) demonstrates high initial discharge capacity. However, the existence of an unstable P3 phase leads to a fast capacity fade that is adverse to engineering applications. Herein, the introduction of inactive magnesium to partially replace electrochemically active nickel of Na 0.5 Ni 0.3 Mn 0.7 O 2 is proposed to reinforce the structural stability of the material. It is found that magnesium incorporation can suppress the growth of the P3 phase, and proper substitution of magnesium for nickel can even harvest pure P2 phase material. The X-ray diffraction (XRD) pattern reveals that the prepared Na 0.5 Ni 0.2 Mg 0.1 Mn 0.7 O 2 (Mg-0.1) is a structure-stable P2-type material. The fabricated Na 0.5 Ni 0.2 Mg 0.1 Mn 0.7 O 2 SIB cathode exhibits acceptable initial discharge capacity, tunable rate capability, and satisfactory cycling stability. These superior electrochemical properties account for low electrochemical resistances, fast Na + diffusion kinetics, and the extremely stable structure of the P2-Na 0.5 Ni 0.2 Mg 0.1 Mn 0.7 O 2 material, which are revealed by means of electrochemical impedance spectra and ex situ XRD technologies.

Stable Electrochemical Properties of Magnesium-Doped Co-Free Layered P2-Type Na0.67Ni0.33Mn0.67O2 Cathode Material for Sodium Ion Batteries

“…Diffraction peaks of the four groups of samples matched well with the standard PDF card (PDF: #54-0894). 30 Four groups of samples belong to the hexagonal system, with the P63/mmc spatial group, indicating that these samples have a P2-type layered structure (Supporting Information Figure S1). The diffraction peak of the NiO impurity phase is observed in the doped samples, which is related to the dissolution limit of nickel ions in the P2 phase structure.…”

“…The atomic compositions (Ni, Mn, Mg) of the three prepared compounds were measured by ICP-AES, as listed in Table S1, and the results approach the nominal values. Diffraction peaks of the four groups of samples matched well with the standard PDF card (PDF: #54-0894) . Four groups of samples belong to the hexagonal system, with the P 63/ mmc spatial group, indicating that these samples have a P2-type layered structure (Supporting Information Figure S1).…”

Significant role of magnesium substitution in improved performance of layered O3‐Na‐Mn‐Ni‐Mg‐O cathode material for developing sodium‐ion batteries

“…Hence, the chemical ratio plays a vital role for enlightening electrochemical performances of all the prepared materials 51,52 . Higher content of sodium (Na) increased the capacity and limited amount of Magnesium (Mg) swap improved structural stability of the NMN (Mg‐0.1) and NMN (Mg‐0.05) cathode materials 23‐26 . The substitution of Mg content increases the d‐spacing of the prepared materials with increase in concentration.…”

“…Hou et al 23 observed that limited quantity of Mg substituted P2‐type Na 0.67 Mn 0.67 Mg 0.1 Ni 0.23 O 2 cathode material provides outstanding cycling performance and good structural stability. Besides, Mg deputized manganese based P2‐type cathode materials are sufficiently available in literature, such as P2‐Na 0.67 Ni 0.25 Mn 0.65 Mg 0.1 O 2, 24 P2‐Na 0.5 Ni 0.2 Mn 0.7 Mg 0.1 O 2 , 25 and P2‐Na 0.67 Ni 0.28 Mn 0.67 Mg 0.05 O 2 26 but Mg deputized manganese based O3‐type cathode materials are limited.…”

Preparation and Electrochemical Performance of Reduced Graphene and SnO2 Nanospheres Composite Materials for Lithium‐Ion Batteries and Sodium‐Ion Batteries

“…To solve this problem, we need to exploit electrode materials with high energy density and excellent cycle performance. [4][5][6] In the preparation of batteries, electrode materials and electrolytes play an important role in the overall performance and practical application value of batteries. As the key electrode material, the anode material has always been the research hotspot and focus.…”