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Supporting Information
A Strategy of Selective and Dendrite-Free Lithium Deposition for
Lithium Batteries
Jingwei Xiang a, Ying Zhao b, Lixia Yuan a*, Chaoji Chen a, Yue Shen a, Fei Hu a, Zhangxiang
Hao a, Jing Liu a, Baixiang Xu b & Yunhui Huanga*
a State Key Laboratory of Material Processing and Die & Mold Technology, School of
Materials Science and Engineering, Huazhong University of Science and Technology,
Wuhan 430074, P.R. China.
b Mechanics of functional materials, Department of Materials Science, TU Darmstadt
Jovanka-Bontschits-Str. 2, 64287 Darmstadt, Germany.
*Correspondence to: [email protected], [email protected]
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Chemo-mechanical Simulations
Generally, Li deposition occurs when the reduced Li-ions on the surface of the electrode is faster than
those intercalated. In that case, the Li-ions concentration on the surface is higher than the critical
concentration, and the redundant Li deposits on the surface of the electrode. Higher current density
leads to more Li deposition due to faster Li reduction on the surface; alternatively, decreasing Li
diffusion inside the particle also gives the Li deposition[1-2]. On this base we performed a coupled
chemo-mechanical simulation with different particle geometry and current density, as shown in
Figure1. The details of the model are as followed. More detailed information can be found in the work
of Stein.[3]
The diffusion process of Li is governed by the equation
∂ c∂ t
=−J i ,i (1)
where c is the mole concentration of Li in the particle and the flux J i is determined by
J i=−D {[1−2c (1−c ) ] c ,i−Ω
RTc (1−c ) σh , i}. (2)
In Eq.(2), D ,Ω ,R ,T are diffusivity, partial molar volume, gas constant, temperature,
respectively. The term containing the hydrostatic stress σ h which represents a drifting effect
from the stresses to the diffusion process that the Li atom is driven away from the
compression region. Since the current is given as a constant, on the particle surface, a constant
flux boundary condition is given
J i ni=Japplied . (3)
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For the mechanical part, the local force balance in the particle holds
σ ij, j=bi (4)
where the stresses is expressed as
σ ij=Cijkl [εij−(c−cref ) Ω3
δkl ] (5)
with ε ij being the strain tensor.
The surface tension is applied as a boundary condition for the mechanical part
σ ij n j=τ i . (6)
Since the parameters, especially the surface tension is not easy to be measured, no
quantitative conclusions can be made.
Figure S1. TEM images of carbon nanofibers based on different ratios: 1:10 (A), 5:10 (B),
8:10 (C).
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Figure S2. FTIR spectra of LCNF.[4-5]
Figure S3. SEM images of LCNF based on different PAN/PS weight ratio: 1:0.5 (A), 1:0.8
(B), 1:0.2 (C).
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Figure S4. The cross-section SEM images of LCNF (a) and SCNF (b) after 8 mAh/cm -2 Li deposition.
Figure S5. SEM images of bare Li electrode (A) and oblique section of LCNF (B) after 30
cycles at a current density of 1 mA cm-2 for 8 mAh cm-2. XRD patterns for LCNF before and
after Li deposition (C).
Figure S6. SEM image of Cu foil after 8 mAh cm-2 Li deposition: (a) top view; (b) cross-section.
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Figure S7. Nitrogen adsorption-desorption isotherm of the LCNF.
Figure S8. Coulombic efficiency of different electrode cycled in ether-based electrolyte at 0.4
mA cm-2.
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Figure S9. Coulombic Efficiency of Cu foil as work electrode at different current density in ether-
based electrolyte.
Figure S10. Graphical illustration of the Li storage mechanism. (A) Li deposition process on
the bare LCNF matrix (black). (B) Li deposition process on the LNafion-LCNF (black)
matrix. (C) The protective mechanisms of the Nafion layer inside the channels of
LCNF@LNafion during the electrode process.
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Figure S11. Cycle performance of Li-LCNF@LNafion and LiFePO4/ 1.8 mAh Li-Cu cells
paired with LiFePO4 in different electrolytes.
References
[1] P. Bai, J. Li, F. R. Brushett, M. Z. Bazant, Energy Environ. Sci. 9 (2016) 3221.
[2] J. H. Han, E. Khoo, P. Bai , M. Z. Bazant, Sci. Rep. 4 (2014) 7056.
[3] P. Stein, Y. Zhao, B. X. Xu, J. Power Sources 332 (2016) 154.
[4] K. Hidcto, T. Kohji, Polymer Journal 29 (1997) 557.
[5] S. Dalton, F. Healtey, P. M. Budd, Polymer 40 (1999) 5531.
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