PDF Publication Title:
Text from PDF Page: 073
Figure 2.5.2. Degradation and failure modes depicted for Li-ion batteries. From Ref. 1. Lithium metal anodes: Rechargeable batteries with lithium metal anodes have been earnestly pursued for decades because they promise very high energy densities, but their commercial deployment has been limited. The tendency to form dendrites or mossy deposits upon repeated stripping and plating of lithium has severely limited the cycle life of these devices and presents serious safety hazards. The use of solid rather than liquid electrolytes ameliorates these problems. Thin film devices utilizing glassy LiPON electrolytes have been cycled successfully thousands of times,5 but they do not completely eliminate these tendencies. Despite intensive investigations of Li-metal batteries, their challenges have not yet been solved. In addition to the aforementioned issues with Li stripping and plating, they have not yet been able to meet practical demands. Advanced Li-polymer batteries can achieve extended performance of 1-10 mAh/cm2 at currents of 1 mA/cm2 with a minimum of excess Li metal, but only at elevated temperatures. Upon extended cycling, Li metal anodes have been reported to form hard impurity agglomerates in Li/polymer batteries6 or wavy ridges leading to islands in Li thin- film batteries.7 Sulfur and air cathodes: In addition to problems at the anode, processes occurring at the cathode may contribute to premature failure of batteries utilizing Li metal anodes. In the case of sulfur8 or air9 electrodes, for example, insoluble and insulating products of the redox reactions, such as Li2S or Li2O2, deposit on electrode surfaces, eventually preventing passage of current. The factors that limit lifetimes of “beyond lithium ion” battery systems such as Na-ion10 or those based on multivalent ions11 are less well-understood and highly system-specific. Thin film solid-state batteries: Thin film batteries based on the LiPON glassy electrolyte are largely constructed with LiCoO2 cathodes and Li anodes, although a host of other anode and cathode materials have been used in laboratory research.5 Such thin film batteries are, in some ways, simpler than Li-ion batteries, with fewer components, simple layered geometry, and stable performance of the electrolyte over a wide voltage range. Because LiPON does not react at cell voltages up to 5 V, the electrolyte is not consumed as it is for the liquid-electrolyte cells, avoiding degradation pathways associated with SEI formation. Figure 2.5.3 compares a thin-film Li/LiPON/LiMn1.5Ni0.5O4 cell with solid electrolyte to a cell having the same electrode films with a standard organic electrolyte.12 Such a comparison is valuable for demonstrating the intrinsic stability of the disordered LiMn1.5Ni0.5O4 spinel cathode for extended cycling. In general, comparing thin film batteries with solid electrolytes to Li-ion batteries with liquid electrolytes may provide ways to distinguish liquid-electrolyte contributors to degradation from more electrode material processes related to cycling, such as phase changes and lattice stresses. Electrochemical capacitors: Capacitors play an important role in storage technology, providing high power and long cycling advantages compared to batteries. Double layer capacitors exhibit significant self-discharge, believed due to the relatively weak interaction between the electrode and the electric double layer.13 Issues of self-discharge also plague pseudo-capacitive materials despite the fact that they also store charge via faradaic reactions.14 Electrochemical capacitors may also fail abruptly due to mechanical breakdown of electrode materials. For example, in some metal oxides, repetitive insertion/deinsertion of Li ions causes strain hardening, NEXT GENERATION ELECTRICAL ENERGY STORAGE PRIORITY RESEARCH DIRECTION – 5 67PDF Image | Next Generation Electrical Energy Storage
PDF Search Title:
Next Generation Electrical Energy StorageOriginal File Name Searched:
BRN-NGEES_rpt-low-res.pdfDIY PDF Search: Google It | Yahoo | Bing
Sulfur Deposition on Carbon Nanofibers using Supercritical CO2 Sulfur Deposition on Carbon Nanofibers using Supercritical CO2. Gamma sulfur also known as mother of pearl sulfur and nacreous sulfur... More Info
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)