Enhanced Electrochemical Performance of the Lithium-Manganese-Rich Cathode for Li-Ion Batteries with Na and F CoDoping

Abstract

The lithium-manganese-rich layered oxide cathode (LMR-NMC), xLi2MnO3·(1 – x)­LiMO2 (M = Co, Ni, and Mn), is on demand because of its high specific capacity of over 250 mA h g–1 between the voltage range 2.0–4.8 V (vs Li/Li+). Because of the requirement of activating the Li2MnO3 phase in the first cycle, oxygen extraction from the lattice structure occurs. Consequently, capacity fading and voltage fading during cycling are still major obstacles to the commercialization of LMR-NMC in battery applications. Here, codoping Na and F into LMR-NMC via facile hydroxide coprecipitation followed by solid-state reaction is introduced. Na and F are partially substituted into Li and O sites, respectively. These dopant ions enlarge the Li slab, which in turn eases Li diffusion and minimizes oxygen loss, thereby stabilizing the structure. The codoped sample exhibits both high capacity retention (97%) and high voltage retention (91%) over 100 cycles with an initial discharge capacity of 260 mA h g–1 at 0.1 C. Compared to other reports on LMR-NMC as obtained by coprecipitation, results from this study show the best capacity retention. The developed codoping approach may provide a new strategy for designing high-performance LMR-NMC cathodes for next-generation lithium ion batteries.

Technological innovation vs. tightening raw material markets: falling battery costs put at risk

“…For less range-sensitive applications, these include lithium iron phosphate (e.g., LFP, LMFP) and manganese-rich (e.g., NCM307) chemistries. For more range-sensitive applications, development efforts should focus on overcoming the durability and safety challenges that currently impede the widespread adoption of alternative chemistries promising high energy density, such as high-voltage spinel oxide chemistries (e.g., LNMO with molar nickel share among transition metals r 50%; to date suffering from rapid capacity decay due to electrolyte degradation [63][64][65] ) and lithium and manganese-rich chemistries (e.g., Li a Ni x Mn y Co z O 2 , a Z 1, x r 0.2, y Z 0.5; suffering from voltage and capacity fade, and voltage hysteresis due to oxygen release and transition metal migration triggered by oxygen redox activity 6,65,66 ). Further, respective companies should evaluate options for vertical integration of sustainable nickel mining and refining to reduce price risks at global markets, and to gain competitive advantages by a reduced environmental production footprint and an elimination of margins for intermediate nickel products.…”

Upgrading the Performance and Stability of Lithium, Manganese‐Rich Layered Oxide Cathodes with Combined‐Formic Acid and Spinel Coating Treatment

“…The LMR cathode is synthesized via hydroxide co-precipitation and solid-state reaction as reported in our previous work. [40] The LMR cathode particles were then washed with distilled water at 60 °C, or 0.05 M formic acid (Sigma-Aldrich) at room temperature for 24 h at a ratio of 1 g/1 mL solution. The powders were submerged without agitation for the majority of the washing step to prevent particle breakage whereas the time of 24 h was fixed for all conditions to make sure all LMR particles were thoroughly washed in the specified solutions.…”

Progress of the Elements Doped NaFeO2Cathode Materials for High Performance Sodium‐ion Batteries

“…[65,66] Second, doping F ions can also adjust the binding energy of oxygen and the transition metal forms a strong bond with F. [67,68] Third, dissociation of the electrolyte and the oxygen in the crystal lattice loss can produce hydrogen fluoride (HF), thus preventing damage to the cathode electrode. [69,70] Therefore, F [62] The full cell of O3-Na 0.9 [Cu 0.22 Fe 0.30 Mn 0.48 ]O 2 /Hard carbon: (c) Long-term cycling performance at 0.5 C; (d) Discharge curves of the full cell cycled at constant charge/discharge rates from 0.5 C to 6 C. [62] Reproduced with permission from Ref. [62].…”