Journal of Power Sources 136 (2004) 80–87 Cu 3 P as anode material for lithium ion battery: powder morphology and electrochemical performances  Marie-Pierre Bichat a , Tatiana Politova a , Heriberto Pfeiffer b , Franck Tancret b , Laure Monconduit a , Jean-Louis Pascal a , Thierry Brousse b , Frédéric Favier a,∗ a Laboratoire des Agrégats Moléculaires et Matériaux Inorganiques, UMR 5072 CNRS Université Montpellier 2, F 34095 Montpellier Cedex 05, France b Laboratoire de Génie des Matériaux, Ecole Polytechnique de l’Université de Nantes, BP50609, 44306 Nantes Cedex 3, France Received 9 January 2004; accepted 3 May 2004 Available online 17 July 2004 Abstract Cu 3 P is studied as a potential material to be used as anode in a Li-ion battery. Depending on the synthetic route, solvothermal, ball-milling (with or without annealing), spray method or ceramic, used for its preparation, Cu 3 P shows various particle sizes and crystallinities. The electrochemical reactivity towards lithium of these various Cu 3 P powders is discussed through galvanostatic and potentiodynamic measurements, electron microscopy techniques, and X-ray diffraction on powder. Electrochemical performances, especially initial capacity and capacity retention, are shown to strongly correlate to the powder morphologies: small particle size favors high capacity values and the operation scan rate affects the capacity depending on the degree of crystallinity of the powder. On other hand, the battery capacity retention is better with microsized powders. © 2004 Elsevier B.V. All rights reserved. Keywords: Cu 3 P; Morphology; Anode; Lithium ion battery; Size; Crystallinity 1. Introduction Conceptually, electrode materials for Li-ion batteries have to show crystalline as well as electronic structures allowing the reversible intercalation of a large amount of lithium at a suited flat potential. Furthermore, low molecular weight and high molar density are required for greater specific and volumic capacities, as well as good electronic and Li + conductivities, especially at the solid–electrolyte interface. Technologically, electrode materials have to show a long and safe cycle life with limited, if any, morphological issues. Manufacturers are also concerned on the difficulty of prepar- ing and handling the material. Some other characteristics remain more specific to each type of electrodes, anodes and cathodes. Refining these key parameters is the main objec- tive for several research groups [1]. However, inside the bat- tery, the reaction of lithium with the active material begins at the solid–liquid–electrolyte interface before any lithium diffuses through the material. How do the electronic and  Supplementary data associated with this article can be found at doi: 10.1016/S0378-7753(04)00550-6. ∗ Corresponding author. E-mail address: fredf@univ-montp2.fr (F. Favier). topological characteristics of the interface influence the elec- trochemical reactivity of the active material toward lithium? The morphology of electrode materials has become impor- tant with the development of new synthetic routes, such as ball-milling [2,3] and the observed corresponding enhance- ment of the electrochemical performances. An approach to answer this question is to prepare a single compound using methods leading to various powder morphologies, particle sizes and crystallinities, and then to compare the corre- sponding electrochemical behavior. Some work has been done in this field using a similar strategy [4,5]. The focus was however, more on the relationship between particle size and electrochemical reactivity rather than on the effect of powder morphology as a whole; particle size, surface state, and “bulk” crystallinity. Following our previous results on lithiated metal pnictides [6], nano to micro-structured first row transitional metal phosphides, with their easy prepara- tion and good tuning of both particle size and crystallinity, have appeared as good candidates for the design of new an- odes in the Li-ion battery. In this paper, we present our first results on copper phosphide, Cu 3 P. Depending on the syn- thetic route, solvothermal [7,8], ball-milling, spray [9] or high temperature (or ceramic) [10], Cu 3 P has shown various particle sizes and crystallinities. Electrochemical reactivity 0378-7753/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jpowsour.2004.05.024