The LixVPn4 Ternary Phases (Pn = P, As): Rigid Networks for Lithium Intercalation/Deintercalation

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• 作者：Marie-Liesse Doublet ; Fré ; dé ; ric Lemoigno ; Fré ; dé ; ric Gillot ; and Laure Monconduit
• 刊名：Chemistry of Materials
• 出版年：2002
• 出版时间：October 2002
• 年：2002
• 卷：14
• 期：10
• 页码：4126 - 4133
• 全文大小：210K
• 年卷期：v.14,no.10(October 2002)
• ISSN：1520-5002

文摘

We present the ternary phases Li_xVPn₄ (Pn = P, As) as new materials for the negativeelectrode in lithium-ion batteries. Associated with a large variation of lithium content performula unit (3 x 7.5 for P and 3 x 11 for As), these materials show a higher specificcapacities in their first charge/discharge cycle than the graphite (550 mA·h/g for Pn = Pand 530 mA·h/g for Pn = As vs 372 m·Ah/g for C_gr) and open new routes for the design ofnew types of rechargeable Li-ion batteries. High-temperature syntheses, X-ray diffractionanalyses, and first-principle electronic structure calculations give evidence of remarkablestability of the Li_xVPn₄ crystal structure upon various lithium compositions. Owing to ratherstrong covalent V-Pn bonds, the host matrixes behave as structurally stable networks ofweakly interacting tetrahedra, able to store (respectively, release) a large number ofadditional electrons (correlatively with the intercalation (respectively, deintercalation) ofLi⁺ in the host matrix) into a nearly nonbonding Pn-Pn band. This leads to very weakvolumetric variations (<1%) of the unit cells upon cycling compared to what is usuallyobserved in the negative electrode materials such as alloy compounds. The cyclingperformances of the new, promising Li_xVPn₄/Li cells are currently under investigation.