Page 170 - Handbook of Battery Materials

4.3 Physical Properties and Chemical Composition of EMD 139

Angstrom
10 2 10 3 10 4 10 5
500

A
100
B S. G.
A : 1.0g/cc
50 C
B : 4.0g/cc
C : 5.0g/cc
Surface Area (m 2 /g) 10 5
EMD

1

0.1
0.01 0.1 1 5 10
one side of cube, micron

Figure 4.15 Surface area of solid cubes of various specific gravities.

d w

d = 50 Å w is 8-12 Å
(a) Computer Pore (b) Cavity
(calculated) (Proposed hypothesis)

Figure 4.16 (a,b) Cross-section of pore and cavity in EMD.
4.3.2
Closed Pores

The presence of closed pores was demonstrated by Kozawa [21] by measuring the
BET surface area of EMD samples of various particle sizes. Kozawa’s new method
for the determination of the closed pore is based on the relationship of the BET
surface area and the particle size, by extrapolating the surface area value to zero
particle size (Figure 4.17). Table 4.8 shows the percentage of closed pores of various
EMD samples.