An innovative electrode, formed from tin nanoparticles embedded in a carbon matrix is obtained. The compact, composite structure maintains the benefits of nanodimensions but keeps a surface area small, reducing its reactivity and the associated safety risks. The Sn-C electrode has a life extending to several hundreds of cycles with a delivered constant capacity as high as 500 mA h g(-1) (see figure) and exceptional performance in a new type of high-performance, advanced lithium-ion battery.