Activated carbon fiber (ACF) containing Sn nanoparticles were prepared by impregnation and were investigated as a negative electrode material in lithium batteries. The tin particle size was controlled by selecting an ACF with an adequate surface structure. This Sn/ACF composite cycled versus Li metal showed a first discharge capacity as high as 200 mAh g(-1) e. compared to the pristine ACF which showed only 87 mAh g(-1). Excellent cyclability with these composites was obtained with ACF BET SSA as large as 2000 m(2) g(-)1 and 30 wt.% Sn.