LiFePO4 has emerged as the winning cathode material for a new generation of Li-ion batteries that are increasingly used for hybrid and electric vehicles, due to its remarkable electrochemical properties. The present review gives the state of the art in the understanding of the properties of this material and the other members of the same family. We discuss the effects of the decrease of the size of the particles down to circa 20 nm; some of them have been misunderstood or are still open questions. All of them are important to determine the trends in the research and development on this family of materials in the future. The cells' properties are also reviewed with both the graphite and more recently the Li4Ti5O12 anodes, the last one providing outstanding performance in terms of cycling life and power that make them promising not only for electric vehicles, but also to solve for intermittence locally in smart grids.