Molecular Wiring of Insulators: Charging and Discharging Electrode Materials for High-Energy Lithium-Ion Batteries by Molecular Charge Transport Layers

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• 作者：Qing Wang ; Nick Evans ; Shaik M. Zakeeruddin ; Ivan Exnar ; Michael Gr&auml ; tzel
• 刊名：Journal of the American Chemical Society
• 出版年：2007
• 出版时间：March 21, 2007
• 年：2007
• 卷：129
• 期：11
• 页码：3163 - 3167
• 全文大小：150K
• 年卷期：v.129,no.11(March 21, 2007)
• ISSN：1520-5126

文摘

Self-assembled monolayers (SAMs) of redox-active molecules on mesoscopic substrates exhibittwo-dimensional conductivity if their surface coverage exceeds the percolation threshold. Here, we showfor the first time that such molecular charge transport layers can be employed to electrochemically addressinsulating battery materials. The widely used olivine-structured LiFePO₄ was derivatized with a monolayerof 4-[bis(4-methoxyphenyl)amino]benzylphosphonic acid (BMABP) in this study. Fast cross-surface holepercolation was coupled to interfacial charge injection, affording charging and discharging of the cathodematerial. These findings offer the prospect to greatly reduce the amount of conductive carbon additivesnecessary to electrochemically address present metal phosphate cathode materials, opening up thepossibility for a much improved energy storage density. When compared at equal loading, the rate capabilityis also enhanced with respect to conventional carbon-based conductive additives.