Despite many newly proposed concepts and a variety of materials applied, Li-ion batteries remain as the most reliable energy storage system for a broad range of applications. As a result, intense research is underway worldwide for further enhancement of their key parameters such as energy/power densities, charge/discharge rates and safety. These attempts include discovering new cathode/anode materials, electrolytes, additives, binders and optimization of metal collectors. Here we present Li-ion battery based on freestanding anode and cathode electrodes consisting only of active material and single wall carbon nanotubes, eliminating the need of additives, binders and collectors. Since, those components constitute about a 30 % in a battery weight, then it is expect an increase of energy density. Our freestanding electrodes have been obtained, for the first time, by a one-step in situ mixing of the active material powder with pristine carbon nanotubes, providing homogenous mixing, preventing nanotubes bundling, and thereby reducing percolation point of electrical conductivity of obtained electrodes. Controlling this parameter is also important for enhancement of power density. Moreover, our method allows continuous production of freestanding, flexible sheets of electrodes that open new perspectives for powering flexible electronics and sensors/actuators for wearable devices. The results of battery performance, evaluations, and impedance studies depending on C-rates, nanotube concentrations, density of electrodes and their conductivities will be presented for two different configurations: coin and pouch cells for half and full cells, respectively.