Electrolyte failure mechanisms

Based on our observation, a membrane degradation and failure mechanism under the RH cycling, a pure mechanical effect is theorized as the following sequence electrode-microcracking- - crazing initiation at the electrode/electrolyte interface - crack growth under stress cycling- -fast fracture/instability. 

Lowrie, F.L. and Rawlings, R.D., Room and high temperature failure mechanisms in solid oxide fuel cell electrolytes, Journal of European Ceramic Society 20, 2000, 751. 

Metal Failure in Electrolytes Under Mechanical Stresses... 

Furthermore, for pseudocapacitive materials, the cycle stability is a major concern. Besides the repeated ion intercalation/deintercalation-related failure mechanism, it was also found that the decrease of the capacitive performance after long-term charging/discharging cycling might also be related to the dissolution of electrode materials in alkaline electrolytes [142]. Joseph et al. [142] found the cycling stability of Ni3(N03)2(0H)4 in LiOH was higher than that in KOH and NaOH electrolytes. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis showed the evidence of the Ni dissolution into the electrolyte and found the dissolution of... 

In order to understand the aging or failure mechanisms of the IL electrolyte-based EDLCs, the electrochanical decomposition of the ILs in EDLCs beyond the ESPW has been investigated [35,102,103]. Using in situ infrared and electrochemical spectroscopy methods, Romaim et al. [102] reported that for [EMIM][BF4] IL electrolyte, imidazolium cation dimerized and led to the formation of l,5-diethyl-4,8-dimethyl-l,4,5,8-tetraazaf-ulvalene at the electrode potential below -2 V (vs. Ag/AgCl wire in the same IL), while the formation of BF3 complexes with BF4 anion and fluorination of the cations occurred... 

Aurbach, D. Zinigrad, E. Cohen, Y. Teller, H. A short review of failure mechanisms of hthium metal and hthiated graphite anodes in hqirid electrolyte solirtions. Solid State Ionics, 2002,128,405-416. 

Figure 1.12. Failure mechanism controlled by the evolution of porosity -within the Si electrode. Appearance of large-scale pores (10 cycles). Progressive filling of these pores by products resulting from the electrolyte degradation, making it increasingly difficult forLf ions to percolate. (Reprintedfrom [PHI 13a] with permission. Copyright 2014. The Owner Societies). Fora color version of the figure, see www.iste.co.uk/dedryvere/electrodes.zip...

Steppan, J., Roth, J., Hall, L., et al., Review of Corrosion Failure Mechanisms During Accelerated Tests, Electrolytic Metal Migration, Journal of the Electrochemical Society. Vol. 134, No. 1, 1987, p. 175. 

Changes in both the adhesion values obtained in before-and-after testing and in the failure loci can reveal quite a bit about aging and failure mechanisms. Changes in barrier properties, measured by electrochemical impedance spectroscopy (EIS), are important because the ability to hinder transport of electrolyte in solution is one of the more important corrosion-protection mechanisms of the coating. 

Although the cellophane replacement used for the gas barrier alleviates the above failure mechanism, it introduces another problem, if the cell is not manufactured and maintained properly. Without proper additives in the electrolyte, which find their way into the cadmium electrode during cycling, the cell can lose capacity in the negative electrode. The role of supplying an oxidized cellophane expander for the cadmium electrode needs to be replaced by cellulose derivatives and other additives to maintain the negative capacity."... 

Metal-air batteries need to absorb oxygen from the surrounding environment. However, several major failure mechanisms in metal-air batteries are also associated with this open operation structure. Electrolyte evaporation (i.e., dry-out) can disable these batteries prematurely, and electrolyte flooding (by water diffusion) can diminish the availability of gas diffusion channels in the porous electrode. 

The combination of the multiple pertinent physics in the battery cell, incorporating the interplay of manufacturing- and service-induced loads and failure mechanisms, will surely inform advanced modeling. Of the commonly recognized battery performance degradation mechanisms, namely electrolyte decomposition, active material dissolution, passive layer formation, lithium deposition, and mechanical failure of battery materials, mechanical failure is the least understood at present, although there is ample evidence of the importance of these effects, and they are the subject of this chapter. 

Furthermore, there are other well-known failure mechanisms in li-ion batteries, but it is not clear how and how much cell mechanics is interrelated with those failure mechanisms dissolution of electrode materials has been known to result in a loss of capacity, as in the case of Mn dissolution from IiMn204 cathodes. Instability of the electrolyte is another well-known failure mechanism in Li-ion batteries decomposition of the liquid electrolyte includes reaction of the solvent at electrode surfaces to form a passivation layer (i.e., soHd-electrolyte interface, SEI layer), resulting in an increase in internal resistance and excessive polari2ation. 

Cell materials under certain conditions may undergo undesirable phase transition that leads to cell capacity fade. Jahn-Teller distortion occurring in IiMn204 at 280 K is an example of this kind of failure mechanism related to the intrinsic stability of the molecular structure. Upon particle fracture, the contact surface area between particles and electrolyte greatly increases, and this may strongly affect electrode dissolution and the stabiUty of the SEI layer. 

Improving the cycle life will reduce satelhte cycle life costs by reducing the frequency of battery replacement. This may be accomplished by modifying the state-of-the-art design to eliminate identified failure mechanisms and by using 26% rather than 31% (SOA) KOH electrolyte. 

Schematic diagram (a) and an SEM photograph (b) of two triple-track test structures that are used to study electrolytic corrosion mechanisms along with the effectiveness of passivation layers. The structure shown on the right was encapsulated and then exposed to HAST conditions until failure. This particular structure is part of the integrated test device shown previously in Kgure 19.5. These test devices contain eight triple-track sections (the left set with windows in the passivation layer) and exposed wirebond pads.

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