High-Capacity Molecular Scale Conversion Anode Enabled by Hybridizing Cluster-Type Framework of High Loading with Amino-Functionalized Graphene

详细信息    查看全文

• 作者：Junjie Xie ; Ye Zhang ; Yanlin Han ; Chilin Li
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：May 24, 2016
• 年：2016
• 卷：10
• 期：5
• 页码：5304-5313
• 全文大小：724K
• 年卷期：0
• ISSN：1936-086X

文摘

Exploring high-capacity anodes with multielectron reaction, sufficient charge/mass transfer, and suppressed volume expansion is highly desired. The open frameworks consisting of independent structure units, which possess conversion reaction potentiality, can meet these demands and show advantages over routine insertion-type open frameworks with at most one-electron transfer or conversion materials with compact ligand linkage. Here, we report a class of electrochemically stable cluster-like polyoxometalates (POMs) as such open framework anodes. Their high loading and low solubility are enabled by Al- or Si-driven polymerization and hybridization with positively charged graphene, which immobilizes polyanions of POMs and improves their electric contact. Al-based POM composite (NAM–EDAG) for Li-storage achieves a high reversible capacity above 1000 mAh g^–1 and tolerates a long-term cycling with more than 1100 cycles and a current density up to 20 A g^–1. A six-electron conversion reaction occurring at molecular scale and the consequent optimized distribution of products benefiting from original open framework are also responsible for the high electroactivity. POM-based open frameworks give inspiration for exploring advanced, less soluble (or insoluble) framework materials made up of electroactive molecule or cluster moieties for Li- and Na-storage.