Probing Lithiation Kinetics of Carbon-Coated ZnFe2O4 Nanoparticle Battery Anodes

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• 作者：Fernando Martinez-Julian ; Antonio Guerrero ; Marta Haro ; Juan Bisquert ; Dominic Bresser ; Elie Paillard ; Stefano Passerini ; Germ脿 Garcia-Belmonte
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：March 27, 2014
• 年：2014
• 卷：118
• 期：12
• 页码：6069-6076
• 全文大小：406K
• 年卷期：v.118,no.12(March 27, 2014)
• ISSN：1932-7455

文摘

The investigation of the lithiation鈥揹elithiation kinetics of anodes comprising carbon-coated ZnFe₂O₄ nanoparticles is reported in here. The study confirmed that, as occurring with other conversion electrodes, lithiation of ZnFe₂O₄ nanoparticles is a multistep process involving the presence of intermediate Li鈥揨n鈥揊e鈥揙 phases as precursors for the formation of amorphous Li₂O. A detailed knowledge on the reaction kinetics of the involved electrochemical mechanisms has been achieved by using impedance spectroscopy. It has been observed that lithiation reactions introduce a long delay that limits the electrode charging, not related to diffusion mechanisms. The sloping curve following the conversion plateau of the galvanostatic discharge is connected to a retardation effect in the reaction kinetics. This limitation is seen as an additional resistive process originated by the specific lithiation microscopic features. It is concluded that capacitance spectra allow distinguishing two separate processes: formation of kinetically favored intermediate Li鈥揨n鈥揊e鈥揙 phases and subsequent reaction to produce highly dispersed LiZn and Fe⁰ in an amorphous Li₂O matrix. A detailed electrical model is provided accounting for the overall electrode lithiation process.