Chapter 6
Combinatorial Studies of Compositions
Containing Layered Phases in the Li–Mn–Ni–O
System
6.1 Experimental Design
This chapter deals with the remainder of the Li–Mn–Ni–O phase diagram obtained
with combinatorial samples. The experimental design is the same as that described
in Chap. 5. The objective here is to show supporting evidence for the rest of the phase
diagrams shown in Fig. 5.2.
A few combinatorial samples were imaged by scanning electron microscope
(SEM) as described in Sect. 2.8. Bulk samples with key compositions were also synthesized using the “one-pot” method outlined in Sect. 2.1.2. The helium pycnometer
was used to obtain accurate density measurements of an ordered rocksalt sample
to calculate the concentration of vacancies present in the structure as described in
Sect. 2.11.
6.2 Single-Phase Layered Region
Once again, one challenge with the combinatorial synthesis of samples in the layered region of the triangle is that the samples lose lithium during heating. Figure 6.1a
shows the phase diagram with points resulting from using atomic absorption to determine the composition of the samples after heating. All points included here are
within error bars from the as-dispensed composition. Other samples were synthesized by the same method and characterized by X-ray diffraction (XRD) in order to
determine the phases present. The boundary line from LiNiO 2 to Li 2 MnO 3 is drawn
as a straight line as this seems to agree with the data available but more samples are
required to confirm this. The upper boundary of the layered region was determined
as described in Sect. 6.8 and was in good agreement with the samples shown in
Fig. 6.1a.
Data in this chapter are reprinted from Ref. [12] with permission from the American Chemical
Society.
77
E. McCalla, Consequences of Combinatorial Studies of Positive Electrodes
for Li-ion Batteries, Springer Theses, DOI 10.1007/978-3-319-05849-8_6,
© Springer International Publishing Switzerland 2014
Combinatorial Studies of Compositions
Containing Layered Phases in the Li–Mn–Ni–O
System
6.1 Experimental Design
This chapter deals with the remainder of the Li–Mn–Ni–O phase diagram obtained
with combinatorial samples. The experimental design is the same as that described
in Chap. 5. The objective here is to show supporting evidence for the rest of the phase
diagrams shown in Fig. 5.2.
A few combinatorial samples were imaged by scanning electron microscope
(SEM) as described in Sect. 2.8. Bulk samples with key compositions were also synthesized using the “one-pot” method outlined in Sect. 2.1.2. The helium pycnometer
was used to obtain accurate density measurements of an ordered rocksalt sample
to calculate the concentration of vacancies present in the structure as described in
Sect. 2.11.
6.2 Single-Phase Layered Region
Once again, one challenge with the combinatorial synthesis of samples in the layered region of the triangle is that the samples lose lithium during heating. Figure 6.1a
shows the phase diagram with points resulting from using atomic absorption to determine the composition of the samples after heating. All points included here are
within error bars from the as-dispensed composition. Other samples were synthesized by the same method and characterized by X-ray diffraction (XRD) in order to
determine the phases present. The boundary line from LiNiO 2 to Li 2 MnO 3 is drawn
as a straight line as this seems to agree with the data available but more samples are
required to confirm this. The upper boundary of the layered region was determined
as described in Sect. 6.8 and was in good agreement with the samples shown in
Fig. 6.1a.
Data in this chapter are reprinted from Ref. [12] with permission from the American Chemical
Society.
77
E. McCalla, Consequences of Combinatorial Studies of Positive Electrodes
for Li-ion Batteries, Springer Theses, DOI 10.1007/978-3-319-05849-8_6,
© Springer International Publishing Switzerland 2014