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  • Open Daily: 10am - 10pm
    Alley-side Pickup: 10am - 7pm

    3038 Hennepin Ave Minneapolis, MN
    612-822-4611

Open Daily: 10am - 10pm | Alley-side Pickup: 10am - 7pm
3038 Hennepin Ave Minneapolis, MN
612-822-4611
In Situ Observations of Lithium Dendrite Growth.

In Situ Observations of Lithium Dendrite Growth.

Crowther, Owen

Paperback

Technology & Engineering

Currently unavailable to order

ISBN10: 1243681837
ISBN13: 9781243681836
Publisher: Proquest Umi Dissertation Pub
Pages: 102
Weight: 0.43
Height: 0.21 Width: 7.44 Depth: 9.69
Language: English
Current national policy to decrease the consumption of gasoline highlights the need for alternative fuel vehicles (AFVs). Reducing gasoline usage will lead to two significant benefits: an increase in national energy security and a decrease in greenhouse gas emissions. Electric vehicles (EVs) are an ideal AFV because they are more efficient than conventional automobiles powered by internal combustion engines because they are not limited by the Carnot cycle. Other advantages of EVs are that they do not need any gasoline, have zero tailpipe emissions, and should need less regular maintenance due to their lack of moving parts. Lithium (Li) is an ideal negative electrode material because it is the most electronegative and has the highest theoretical specific capacity of all metals at 3860 mAh g-1. Furthermore, Li metal batteries are the only system with a specific energy high enough to meet long term USABC EV battery goals. Experiments show most metals will form dendrites as the current approaches so-called limiting current, where reaction rate is controlled by the rate of Li+ mass transfer to the electrode. However, dendrites will form during Li deposition for all currents with enough time. This work attempts to discover the mechanism for Li propensity to form dendrites and find ways to stop this dendritic growth. Chapter 1 is an introduction to this work that includes a review of all literature that contains in situ observations of lithium deposition. However, a single reference that studies deposit morphology with varying current densities, solvents, salts, the effect of pulse plating, and promising additives, using a common experimental method is lacking. This work studies the above the parameters using the experimental apparatus described in chapter two. Chapter three shows the effect of varying the DMC to PC electrolyte solvent ratio. In this chapter we show for the first time that lithium dendrite initiation is not due to mass transfer, however, Li deposition quickly becomes controlled by mass transfer after initiation. We also show that the time that the first dendrite is observed increases linearly with a resistance given by the Tafel slope. Chapter four studies two promising additives, vinylene carbonate (VC) and triacetoxyvinylsilane (VS) which are known to improve battery performance. The two additives improve battery performance by different mechanisms. VS delays the formation of dendrites while VC slows the growth of dendrites after they are formed. Chapter five examines the effects of pulse plating. Chapter six also makes a practical recommendation of battery electrolyte and current waveform for optimal lithium metal battery performance.

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