New equivalent stress describes the dicing caused anisotropic breaking strength of silicon dies

Steiert, Matthias; Wilde, Jürgen

doi:10.1109/eurosime.2014.6813872

Cited by 1 publication

(1 citation statement)

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“…200 MPa) and also much lower than that in the constrained anode under the same operation condition. 53,54 It has been widely reported that an electrochemical-mechanical coupling occurs for a LIB anode, that is, the lithiation process would induce mechanical stress in the anode and in turn the stress caused by the lithiation would also block the Li + transport in the anode and thus degrades the reaction kinetics. 41,45 Due to this electrochemical-mechanical coupling effect, the non-uniform stress distribution in the anode (as seen in Fig.…”

Section: Resultsmentioning

confidence: 99%

High-Performance Freestanding Lithium-Ion Battery Si Anode by Weakening the Current-Collector Constraint

Zhang

Yue

et al. 2020

J. Electrochem. Soc.

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Lithium-ion batteries (LIB) with both high volumetric and gravimetric specific capacities are desirable for power sources in microsystems. Si is a promising anode material for the above LIBs. However, its huge volume change combined with strict constraint by the bulky current collector (and/or the substrate) during lithiation/delithiation causes a severe stress and thus rapid capacity fading. Strategies in the literatures help suppress the capacity fading but degrade the anode initial Coulombic efficiency and specific capacities. This work presents a freestanding Si anode with an ultrathin current collector. Unlike those in the literatures whose current collector (and/or the substrate) accounts for the main part, the Si film dominates in this freestanding anode. This causes weak constraint from the current collector, therefore, the Si film can expand/shrink easily and stress induced by Si volume change can be effectively released, thus resulting in good anode cyclability (98.6% retention over 150 cycles). Moreover, the dominant role of the Si film in this anode ensures the anode to have high volumetric (6989 mAh cm −3 ) and gravimetric (2107 mAh g −1 ) specific capacities even when both the Si and current collector are included for calculations. This freestanding anode also displays a high initial Coulombic efficiency of 92.8% due to its small surface area.

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