22
2 Experimental and Theoretical Considerations
Fig. 2.3 The Li–Mn–Ni
oxide triangle illustrating how
samples are synthesized over
entire composition range in a
ternary system
Figure 2.3 illustrates the methodology involved in making samples throughout
the Li–Ni–Mn Gibbs triangle. Samples were made at every intersection point of the
dashed lines, which resulted in 66 different compositions within the triangle. This
was accomplished by making three plates, each holding a 6 × 6 array of samples.
The plates were first cut in half in order to fit into the tube furnace. The three
arrays corresponded to samples within each of the three parallelograms shown in
Fig. 2.3: NiA 2 B 2 C 2 , LiC 2 A 2 B 2 and MnB 2 C 2 A 2 . This gave 21 compositions that
were repeated on each of the three plates which served as a reproducibility check.
Thus, this method results in a total of 108 samples made at 66 compositions. For
each system, this mapping was done first. Then, as required, arrays were made over
narrower ranges in order to zoom in on compositions of interest. In all cases, there
were some duplicate samples to confirm reproducibility (usually duplicating a few
samples from the original 66).
2.1.2 Synthesis of Bulk Samples
Three different synthesis methods were used to make bulk samples. The simplest
was to use a solid-state reaction such as that used in Chap. 3 to make LiNiO 2 . This
involved grinding NiO (s) (Nova Met, 98 %) with LiOH (s) (Sigma-Aldrich, 98 %)
and heating to high temperature in air. The second bulk synthesis method mimicked
the combinatorial method on a larger scale. This involved mL-scale (usually a total
of about 20–40 mL) mixtures of lithium, manganese and nickel nitrates (from the
same sources as in the combinatorial synthesis). Excess ammonium bicarbonate was
then added to the mixtures in a beaker and stirred for a few minutes. After drying
overnight at 55
◦ C, the samples were heated to 400
◦ C for about 30 min to drive-off
the ammonium carbonate and any other products of the reaction. The samples were
2 Experimental and Theoretical Considerations
Fig. 2.3 The Li–Mn–Ni
oxide triangle illustrating how
samples are synthesized over
entire composition range in a
ternary system
Figure 2.3 illustrates the methodology involved in making samples throughout
the Li–Ni–Mn Gibbs triangle. Samples were made at every intersection point of the
dashed lines, which resulted in 66 different compositions within the triangle. This
was accomplished by making three plates, each holding a 6 × 6 array of samples.
The plates were first cut in half in order to fit into the tube furnace. The three
arrays corresponded to samples within each of the three parallelograms shown in
Fig. 2.3: NiA 2 B 2 C 2 , LiC 2 A 2 B 2 and MnB 2 C 2 A 2 . This gave 21 compositions that
were repeated on each of the three plates which served as a reproducibility check.
Thus, this method results in a total of 108 samples made at 66 compositions. For
each system, this mapping was done first. Then, as required, arrays were made over
narrower ranges in order to zoom in on compositions of interest. In all cases, there
were some duplicate samples to confirm reproducibility (usually duplicating a few
samples from the original 66).
2.1.2 Synthesis of Bulk Samples
Three different synthesis methods were used to make bulk samples. The simplest
was to use a solid-state reaction such as that used in Chap. 3 to make LiNiO 2 . This
involved grinding NiO (s) (Nova Met, 98 %) with LiOH (s) (Sigma-Aldrich, 98 %)
and heating to high temperature in air. The second bulk synthesis method mimicked
the combinatorial method on a larger scale. This involved mL-scale (usually a total
of about 20–40 mL) mixtures of lithium, manganese and nickel nitrates (from the
same sources as in the combinatorial synthesis). Excess ammonium bicarbonate was
then added to the mixtures in a beaker and stirred for a few minutes. After drying
overnight at 55
◦ C, the samples were heated to 400
◦ C for about 30 min to drive-off
the ammonium carbonate and any other products of the reaction. The samples were