Investigation into key interfacial reactions within lithium-ion batteries

manganese deposition on graphite;lithium-ion;capacity fading;5V spinel;core-shell

Vissers, Daniel Richard

关键词: manganese deposition on graphite;    lithium-ion;    capacity fading;    5V spinel;    core-shell;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/90507/VISSERS-DISSERTATION-2016.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Given the concern of global climate change and the understanding that carbon dioxide emissions are driving this change, much effort has been invested into lowering carbon dioxide emissions. One approach to reduce carbon dioxide emissions is to curtail the carbon dioxide emissions from vehicles through the introduction of hybrid electric vehicles, plug-in hybrid electric vehicles, and electric vehicles. Today, lithium cobalt oxide materials are widely used in consumer electronic applications, yet these materials are cost prohibitive for larger scale vehicle applications. As a result, alternative materials with higher energy densities and lower costs are being investigated. One key alternative to cobalt that has received much attention is manganese. Manganese is of interest for its lower cost and favorable environmental friendliness. The use of manganese has led to numerous cathode materials such as Li1-δMn2O4 (4V spinel), Li1-δMn1.5Ni0.25O4 (5V spinel), Li1-δ(Mn1-x-yNiyCox)O2 (layered), Li2MnO3-Li1-δ(Mn1-x-yNiyCox)O2 (layered-layered), and Li2MnO3-Li1-δ(Mn1-x-yNiyCox)1O2-Li1-σMn2O4 (layered-layered-spinel). The work disclosed in the dissertation focuses on two topics associated with these manganese based cathodes. The first topic is the exceptional cyclic-ability of a high power, high energy density, 5V spinel cathode material (Li1-δMn1.5Ni0.25O4) with a core-shell architecture, and the second is the severe capacity fade associated with manganese dissolution from cathodes at elevated operating temperatures. Both topics are of interest to the Li-ion battery industry. For instance, a 5V spinel cathode represents a viable path to increase both the power and energy density of Li-ion batteries. As its name implies, the 5V spinel operates at 5V that is higher than the conventional 4V lithium ion batteries. Since power and energy are directly proportional to the potential, moving from an operating potential of 4V to 5V represents an increase in both power and energy densities of 25%. When the 5V spinel cathode is coupled with a graphite anode, an energy density of up to 240 Wh kg−1 is possible [2]. Secondly, the severe capacity fade associated with the manganese dissolution generally leads to a design with oversized battery packs, like those for the General Motors Chevy Volt, to meet warranty requirements. The result of this work led to deeper understandings of the underlying mechanisms for the exceptional cyclic-ability of the core-shell 5V spinel and for the severe capacity fade associated with manganese dissolution from the cathode and to a rational approach to resolve the severe capacity fade associated with manganese dissolution.