The development of new materials is required to improve the energy density of Li-ion batteries. A new graphite type with optimised physical–chemical characteristics has been studied and developed to improve negative electrode performance. Lithium ion charge and discharge acceptance have been improved by the enhanced intrinsic properties of the material. The new material has higher efficiency electrode porosity/tortuosity, and increases electrical conductivity. This allows better charge performance at low temperatures and discharge performance at high rates. Combined with an optimised electrolyte composition, it also gives low and reproducible fading, good discharge performance in very low temperature conditions, and long term storage at high temperatures. Due to this and other design modifications that will be discussed, a 22% improvement in energy density is obtained in the new generation of Saft Li-ion medium prismatic cells (MP).