Mesoporous Sn Anode Improved Electrochemical Properties

Finally, magnitudes of the stress values of both samples, (a) the Sn and (b] the Sn62Ni3g, were calculated from the deflections measured at 0.01 V vs. L /L using Stoney s equation. As a result, the stress of Sn (osn] and Sn62Ni3g (CTNisJ were (Tsn = 52 [MPa] and %isn = 490 [MPa]. 

As it has been indicated during the discussion of the lithiation process, the relation between the two stress values (osn NiSn) s consistent with the results of the calculation. However, the absolute values of the stress are smaller by an order of 10 -10 than those derived by the calculation. This discrepancy may be partly due to incomplete lithiation of the active material and partly due to inadequacy of the assumptions made for the calculation, such as the formation of voids and cracks, as described in the previous discussion. These phenomena would significantly release the excessive stress that is induced during the reaction of the electrode. 

The difference between the calculation and the experimental results also indicate that the stress-release effect of the Sn electrode is larger than the Sn62Ni39 electrode. This could be due to the different critical yield point of the materials, where Sn could accommodate the stress more than the SngzNisg by plastic deformation. 

Many mesoporous materials with specific structural features (e.g., uniform mesopore size and high surface area] have extensively been investigated. In particular, mesoporous metals with high electroconductivity are very promising for various electrochemical applications. Since the first report by Attard et a/., several mesoporous metals including Sn ° have been prepared by the 

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