Which of the nickel-rich NCM and NCA is structurally superior as a cathode material for lithium-ion batteries?

Jung

ACS Appl. Mater. Interfaces

et al. 2021

Nickel-rich lithium metal oxide cathode materials have recently be en highlighted as next-generation cathodes for lithium-ion batteries. Nevertheless, their relatively high surface reactivity must be controlled, as fading of the cycling retention occurs rapidly in the cells. This paper proposes functionalized nickel-rich lithium metal oxide cathode materials by a multipurpose nanosized inorganic materialtitanium silicon oxidevia a simple thermal treatment process. We examined the topologies of the nano-titanium silicate-functionalized nickel-rich lithium metal oxide cathodes with scanning electron microscopy and quantitatively analyzed their improved mechanical properties using microindentation. The cell containing nickel-rich lithium metal oxide cathodes suffered from poor cycling behavior as the electrolytes persistently decomposed; however, this behavior was effectively inhibited in the cell by nano-titanium silicate-functionalized nickel-rich lithium metal oxide cathodes. Further ex situ analyses indicated that the particle hardness of the nano-titanium silicate-functionalized nickel-rich lithium metal oxide cathode materials was maintained, and decomposition of the electrolyte by the dissolution of transition metals was thoroughly inhibited even after 100 cycles. Based on these results, we concluded that the use of nano-titanium silicate as a coating material for nickel-rich lithium metal oxide cathode materials is an effective way to enhance the cycling performance of lithium-ion batteries.

Section: Resultsmentioning

confidence: 97%

Interface-Stabilized Layered Lithium Ni-Rich Oxide Cathode via Surface Functionalization with Titanium Silicate

Jung

ACS Appl. Mater. Interfaces

et al. 2021

“…There is no distinct difference between pristine NCM and NCMS in the precursors. Figure 5b reveals that both pristine NCM and NCMS have the well-layered structure of α-NaFeO2 type with the space group R-3m [27,28]. However, an Li2SO4 impurity phase around 22° peak is observed in NCMS.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Excessive Sulfate in the Li-Ion Battery Leachate on the Properties of Resynthesized Li[Ni1/3Co1/3Mn1/3]O2

et al. 2021

In order to examine the effect of excessive sulfate in the leachate of spent Li-ion batteries (LIBs), LiNi1/3Co1/3Mn1/3O2 (pristine NCM) and sulfate-containing LiNi1/3Co1/3Mn1/3O2 (NCMS) are prepared by a co-precipitation method. The crystal structures, morphology, surface species, and electrochemical performances of both cathode active materials are studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and charge-discharge tests. The XRD patterns and XPS results identify the presence of sulfate groups on the surface of NCMS. While pristine NCM exhibits a very dense surface in SEM images, NCMS has a relatively porous surface, which could be attributed to the sulfate impurities that hinder the growth of primary particles. The charge-discharge tests show that discharge capacities of NCMS at C-rates, which range from 0.1 to 5 C, are slightly decreased compared to pristine NCM. In dQ/dV plots, pristine NCM and NCMS have the same redox overvoltage regardless of discharge C-rates. The omnipresent sulfate due to the sulfuric acid leaching of spent LIBs has a minimal effect on resynthesized NCM cathode active materials as long as their precursors are adequately washed.

“…[14][15][16][17] Despite the promising aspects of Al 3+ ion substitution, this strategy has been mostly employed in LiTMO 2 and NaTMO 2 , where cationic redox reactions prevail over anionic redox reactions. [18][19][20][21] This causes a lack of understanding of the effect of Al 3+ ion substitution on the electrochemical performance of cathode materials with anionic redox reactions. In this regard, partial substitution of Mn ions with Al 3+ ions may be a prevalent strategy to improve the electrochemical properties of these materials, by bestowing multiple characteristics, such as increasing Na + ion mobility and long-cycling stability, and unlocking anionic redox activity to increase energy density.…”

Section: Introductionmentioning

confidence: 99%

Na_2.4Al_0.4Mn_2.6O₇ anionic redox cathode material for sodium-ion batteries – a combined experimental and theoretical approach to elucidate its charge storage mechanism

et al. 2022