This thesis deals with the development of eco-friendly hard carbon anodes for Na-ion batteries, promising alternatives to the state-of-the-art, Li-ion batteries. In-depth knowledge on the physico-chemical and electrochemical properties of the materials, as well as on the storage mechanisms of Na ions in carbon hosts were emphasized. Three categories of precursors: biomass, biopolymers and synthetic polymers were selected to synthesize hard carbon materials with well-controlled properties. The development of the first eco-friendly phenolic resins, an alternative to the toxic resins, was successfully accomplished. The new resins have led to hard carbons capable of delivering a high capacity of ~ 300 mAh/g. Another aspect of great...