Herein, a hierarchically porous N, S-co-doped carbon material (named as NS-C) was efficiently fabricated from halogenated polymer to meet the targets of the low-cost anode and cathode materials for Li-based batteries. Thanks to its large N (~5.4 at.%) and S (~1.1 at.%) contents, large specific surface area (~1510 m2 g-1), and beneficial pore hierarchy, the NS-C exhibited superior bifunctional performance as anode material and S host for Li-S cathode. The NS-C/sulfur composite (named as S@NS-C) delivered a large capacity of 1125 mAh g-1 at 0.1 C and maintained a capacity of 401 mAh g-1 at 5 C. A continuous long-term use for 200 cycles at 2 C achieved large capacity retention of 80.5%. Furthermore, the NS-C could also serve as anode material for stable Li-ion storage with large capacity, showing very limited capacity fading for over 1000 cycles at both 0.1 and 1.0 A g-1. Moreover, considering the huge amount of halogenated polymer plastic wastes buried, burned, or discarded directedly in the environments, our developed route of simple conversion of halogenated polymers into Li-ion battery anode and S host for Li-S battery cathode is advantageous for both environmental protection and Li-based battery industry.