Stable Electrochemical Properties of Magnesium-Doped Co-Free Layered P2-Type Na_0.67Ni_0.33Mn_0.67O₂ Cathode Material for Sodium Ion Batteries

Abstract

P2-type layered structure manganese-based materials have been reported as the most promising candidate for practical applications of sodium ion batteries because of their high capacity, facile fabrication, low cost, and environmental friendliness. In this work, a novel Cobalt-free layered P2-type Na 0.67 Ni 0.33 Mn 0.67 O 2 cathode material was designed using cation potential, and the cathode material was successfully synthesized by solid-state reaction method. We present an in-depth investigation of the effect of Mg doping on the electrochemical performance and structural stability of Na 0.67 Ni 0.33 Mn 0.67 O 2 by comparing series compositions Na 0.67 Ni 0.33−x Mg x Mn 0.67 O 2 (x = 0, 0.05, 0.1, 0.15, 0.2). The Mgdoping sample Na 0.67 Ni 0.18 Mg 0.15 Mn 0.67 O 2 delivered an initial discharge capacity of 123 mAh•g −1 at 0.1 C in the potential range from 2.0 to 4.3 V. The capacity of the material remained at 92% after 100 cycles at a rate of 0.1 C. Mg ion as an electrochemical inert element can effectively reduce interlayer slip, inhibit phase transition, and stabilize the layered structure. KEYWORDS: Sodium ion batteries, Cathode materials, Na 0.67 Ni 0.33−x Mn 0.67 Mg x O 2 , Manganese substitution, Solid-state reaction method

Completely suppressed high-voltage phase transition of P2/O3-Na0.7Li0.1Ni0.1Fe0.2Mn0.6O2viaLi/Ni co-doping for sodium storage

“…Upon charging to 4.3 V, the valence transitions of Ni 2+ to Ni 3+ and Ni 4+ are observed. 41,42 When the FM electrode is charged to 4.3 V, the binding energies of Mn and Fe move to higher values, respectively, indicating that the redox couples of Mn and Fe both contribute to the capacity of FM upon the initial charge process. When the LN electrode is charged to 4.3 V, the peaks of Mn, Fe and Ni also move to higher values, which confirms the oxidation of Mn 3+ /Mn 4+ , Fe 3+ /Fe 4+ , and Ni 2+ /Ni 3+ /Ni 4+ upon Na + extraction.…”

Zn/Ti/F synergetic-doped Na0.67Ni0.33Mn0.67O2 for sodium-ion batteries with high energy density

“…15 In fact, P2-Na 0.67 Ni 0.33 Mn 0.67 O 2 (NNMO) shows a high theoretical specic capacity (173 mA h g −1 ) and a high average discharge voltage (3.6 V) from 2.0 V to 4.5 V. 16,17 However, if charged above 4.2 V, it displays a rapid decay in capacity because of the P2-O2 phase transition. 18,19 Lattice doping has been investigated as an available strategy. [20][21][22] For example, Kim et al 23 reported that Y-doped P2-type Na 0.67 Ni 0.33−x Mn 0.67 Y x O 2 could enhance the cycle stability.…”

A novel hierarchical book-like structured sodium manganite for high-stable sodium-ion batteries

“…To achieve high-energy SIBs, much attention has been focused on finding suitable cathode materials. 14–17…”

“…To achieve high-energy SIBs, much attention has been focused on nding suitable cathode materials. [14][15][16][17] Among various cathode materials, layered transition metal oxides are considered to be one of the most potential materials because of their high energy density and low cost. [18][19][20][21] In particular, layered sodium manganese oxides (Na x MnO 2+y , y = 0.05-0.25) have attracted extensive attention due to their high theoretical capacity (243 mA h g −1 ), low cost, and low toxicity.…”