Increased thermal conductivity, electronic conductivity, and reversible capacity (i.e., reduced irreversible capacity loss, or ICL) have been demonstrably achievable by compression of anodes into higher volume fraction plates, though excessive compression can impair Li-ion battery performance. In our previous study, we correlated conductivity and compression of these materials. Here, we further investigated the effects of friction and deformability of particles on the compressibility of model carbons of Li-ion anodes. First, we implemented a statistically unbiased technique for generating a range of random particulate systems, from permeable to impermeable arrangements, along with a contact model for randomly arranged triaxial ellipsoidal particles, suitable for implementation in finite element analysis of compression of a random, porous system. We then quantified the relationship between interfacial friction and jamming fraction in spherical to ellipsoidal systems and applied these models to correlate maximum stresses and different frictional coefficients, with morphology (obtained by image analysis) of graphite particles in Li-ion anodes. The simulated results were compared with the experiments, showing that the friction coefficient in the system is close to 0.1 and that the applied pressure above 200kgcm2(200MPa) can damage the materials in SL-20 electrodes. We also conclude that use of maximum jamming fractions to assess likely configuration of mixtures is unrealistic, at best, in real manufacturing processes. Particles change both their overall shapes and relative orientations during deformation sufficient to alter the composite properties: indeed, it is alteration of properties that motivates post-processing at all. Thus, consideration of material properties, or their estimation post facto, using inverse techniques, is clearly merited in composites having volume fractions of particles near percolation onset.

1.
Maleki
,
H.
,
Selman
,
J. R.
,
Dinwiddie
,
R. B.
, and
Wang
,
H.
, 2001, “
High Thermal Conductivity Negative Electrode Material for Lithium-Ion Batteries
,”
J. Power Sources
0378-7753,
94
, pp.
26
35
.
2.
Striebel
,
K. A.
,
Sierra
,
A
,
Shim
,
J.
,
Wang
,
C. -W.
, and
Sastry
,
A. M.
, 2004, “
The Effect of Compression on Natural Graphite Anode Performance and Matrix Conductivity
,”
J. Power Sources
0378-7753,
134
(
2
), pp.
241
251
.
3.
Gnanaraj
,
J. S.
,
Cohen
,
Y. S.
,
Levi
,
M. D.
, and
Aurbach
,
D.
, 2001, “
The Effect of Pressure on the Electroanalytical Response of Graphite Anodes, and LiCoO2 Cathodes for Li-ion Batteries
,”
J. Electroanal. Chem.
0022-0728,
516
(
1-2
), pp.
89
102
.
4.
Wang
,
C. -W.
,
Yi
,
Y. -B.
,
Sastry
,
A. M.
,
Shim
,
J.
, and
Striebel
,
K. A.
, 2004, “
Particle Compression and Conductivity in Li-ion Anodes with Graphite Additives
,”
J. Electrochem. Soc.
0013-4651,
151
(
9
), pp.
1489
1498
.
5.
Kansal
,
A. R.
,
Torquato
,
S.
, and
Stillinger
,
F. H.
, 2002, “
Computer Generation of Dense Polydisperse Sphere Packings
,”
J. Chem. Phys.
0021-9606,
117
, pp.
8212
8218
.
6.
Torquato
,
S.
,
Truskett
,
T. M.
, and
Debenedetti
,
P. G.
, 2000, “
Is Random Close Packing of Spheres Well Defined?
Phys. Rev. Lett.
0031-9007,
84
, pp.
2064
2067
.
7.
Torquato
,
S
, 2000, “
Modeling of Physical Properties of Composite Materials
,”
Int. J. Solids Struct.
0020-7683,
37
(
1-2
), pp.
411
422
.
8.
Torquato
,
S
, 1985, “
Effective Electrical-Conductivity of 2-Phase Disordered Composite Media
,”
J. Appl. Phys.
0021-8979,
58
(
10
), pp.
3790
3797
.
9.
Hales
,
T. C.
, 1997, “
Sphere Packings I
,”
Discrete Comput. Geom.
0179-5376,
17
(
1
), pp.
1
51
.
10.
Yi
,
Y. -B.
,
Sastry
,
A. M.
, and
Philbert
,
M. A.
, 2006, “
Three-dimensional Reconstruction of Cell Boundaries and Interior Organelles from Confocal Microscopy, Using a Combined Delaunay Tesselation/Stochastic Placement Scheme
,” Journal of Computational Physics, in review.
11.
Lubachevsky
,
B. D.
, and
Stillinger
,
F. H.
, 1990, “
Geometric-Properties of Random Disk Packings
,”
J. Stat. Phys.
0022-4715,
60
, pp.
561
583
.
12.
Donev
,
A.
,
Cisse
,
I.
,
Sachs
,
D.
,
Variano
,
E.
,
Stillinger
,
F. H.
,
Connelly
,
R.
,
Torquato
,
S.
, and
Chaikin
,
P. M.
, 2004, “
Improving the Density of Jammed Disordered Packings using Ellipsoids
,”
Science
0036-8075,
303
, pp.
990
993
.
13.
Jodrey
,
W. S.
, and
Tory
,
E. M.
, 1985, “
Computer Simulation of Close Random Packing of Equal Spheres
,”
Phys. Rev. A
1050-2947,
32
, pp.
2347
2351
.
14.
Bezrukov
,
A.
,
Bargiel
,
M.
, and
Stoyan
,
D.
, 2002, “
Statistical Analysis of Simulated Random Packings of Spheres
,”
Part. Part. Syst. Charact.
0934-0866,
19
, pp.
111
118
.
15.
Williams
,
S. R.
, and
Philipse
,
A. P.
, 2003, “
Random Packings of Spheres and Spherocylinders Simulated by Mechanical Contraction
,”
Phys. Rev. E
1063-651X,
67
, p.
051301
.
16.
Vieillard-Baron
,
J.
, 1972, “
Phase Transitions of the Classical Hard-Ellipse System
,”
J. Chem. Phys.
0021-9606,
56
, pp.
4729
4744
.
17.
Donev
,
A.
,
Torquato
,
S.
, and
Stillinger
,
F. H.
, 2005, “
Neighbor List Collision-Driven Molecular Dynamics Simulation for Nonspherical Particles: I. Algorithmic Details II. Applications to Ellipsoids
,”
J. Comput. Phys.
0021-9991,
202
, pp.
409
416
.
18.
ABAQUS/EXPLICIT User’s Manual version 6.3, Hibbitt, Karlsson & Sorensen Inc., 2002.
19.
Shim
,
J.
, and
Striebel
,
K. A.
, 2004, “
The Dependence of Natural Graphite Anode Performance on Electrode Density
,”
J. Power Sources
0378-7753,
130
, pp.
247
253
.
20.
Yoo
,
M.
,
Frank
,
C. W.
, and
Mori
,
S.
, 2003, “
Interaction of Poly(vinylidene fluoride) with Graphite Particles. 1. Surface Morphology of a Composite Film and its Relation to Processing Parameters
,”
Chem. Mater.
0897-4756,
15
, pp.
850
861
.
22.
Yi
,
Y. -B.
,
Wang
,
C. -W.
, and
Sastry
,
A. M.
, 2004, “
Two-Dimensional versus Three-Dimensional Clustering and Percolation in Fields of Overlapping Ellipsoids
,”
J. Electrochem. Soc.
0013-4651,
151
, pp.
A1292
A1300
.
23.
Onoda
,
G. Y.
, and
Liniger
,
E. G.
, 1990, “
Random Loose Packings of Uniform Spheres and the Dilatancy Onset
,”
Phys. Rev. Lett.
0031-9007,
64
, pp.
2727
2730
.
24.
Scott
,
G. D.
, and
Kilgour
,
D. M.
, 1969, “
Density of Random Close Packing of Spheres
,”
J. Appl. Phys., J. Phys. D
,
2
(
6
), pp.
863
866
.
25.
Zinchenko
,
A.
, 1994, “
Algorithm for Random Close Packing of Spheres with Periodic Boundary Conditions
,”
J. Comput. Phys.
0021-9991,
114
, pp.
298
307
.
26.
Pach
,
J.
, and
Agarwal
,
P. K.
, 1995,
Combinatorial Geometry
,
Wiley-Interscience
, New York.
27.
Kansal
,
A. R.
,
Torquato
,
S.
, and
Stillinger
,
F. H.
, 2002, “
Diversity of Order and Densities in Jammed Hard-Particle Packings
,”
Phys. Rev. E
1063-651X,
66
, p.
041109
, Part 1.
28.
Donev
,
A.
,
Torquato
,
S.
,
Stillinger
,
F. H.
, and
Connelly
,
R.
, 2004, “
Jamming in Hard Sphere and Disk Packings
,”
J. Appl. Phys.
0021-8979,
95
, pp.
989
999
.
29.
Donev
,
A.
,
Stillinger
,
F. H.
,
Chaikin
,
P. M.
, and
Torquato
,
S.
, 2004, “
Unusually Dense Crystal Packings of Ellipsoids
,”
Phys. Rev. Lett.
0031-9007,
92
, p.
255506
.
32.
Kelly
,
B. T.
, 1981,
Physics of Graphite
,
Applied Science Publishers
, London.
33.
Dowling
,
N. E.
, 1999,
Mechanical Behavior of Materials: Engineering Methods for Deformation, Fracture, and Fatigue
,
2nd ed.
,
Prentice Hall
, Upper Saddle River, NJ.
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