Juan Ren

A high-efficiency N/P co-doped graphene/CNT@porous carbon hybrid matrix as a cathode host for high performance lithium–sulfur batteries

Heteroatom-doped carbon hybrids containing sp2-hybridized and sp3-hybridized nanocarbons have attracted immense interest as sulfur hosts due to their unique 3D conductive networks and synergistic effect of physical absorption and chemical interaction on suppressing the dissolution of polysulfides. However, the reported carbon hybrids always require a tedious fabrication process, including multistep chemical vapor deposition and a thermally stable catalyst. Therefore, it is highly desirable to exploit a simple, renewable, and scalable strategy to fabricate 3D heteroatom-doped carbon hybrids. Herein, a N, P-co-doped 3D carbon hybrid was successfully fabricated via a one-pot pyrolysis process. Due to the rapid Li+/e− transport among the 3D interconnected porous frameworks and effectively suppressed polysulfide dissolution by physical confinement and chemical interaction, the assembled Li–S batteries exhibit excellent electrochemical performance. The as-obtained cell delivers an ultrahigh initial discharge capacity of 1446 mA h g−1 at 0.1C as well as an excellent rate capability of 921 mA h g−1 at 1C. Additionally, a reversible and stable discharge capacity of 795 mA h g−1 is maintained after 400 cycles at 1C, corresponding to an extremely low capacity decay of 0.034% per cycle. Such a design strategy is eco-friendly and generally applicable to combine the sp2 nanocarbon with sp3 amorphous carbon, which is crucial to construct 3D interconnected hierarchical porous carbons for advanced energy storage for applications in various fields, such as lithium batteries, catalysis and hydrogen storage.

Rational design of a multidimensional N-doped porous carbon/MoS2/CNT nano-architecture hybrid for high performance lithium–sulfur batteries

Exploring a stable and high-efficiency sulfur cathode with strong polarity and a robust porous conductive framework is a critical challenge to develop advanced lithium–sulfur (Li–S) batteries. Herein, a multidimensional N-doped porous carbon/MoS2/CNT (FSC/MoS2/CNT) nano-architecture hybrid is rationally designed and successfully fabricated by the facile pyrolysis and hydrothermal processes. For the nano-architecture composite, the porous carbon embedded with electroconductive acid-treated CNTs effectively enhances the flexibility and constructs a conductive network for rapid ion/electron transfer; specifically, a synergistic action of polar MoS2 and electronegative doped N atoms significantly strengthens the chemical affinity with polysulfides; furthermore, MoS2 exhibits a strong catalytic effect that can improve the redox kinetics of polysulfides. On account of the merits mentioned above, the as-built N-doped porous carbon/MoS2/CNTs@S (FSC/MoS2/CNTs@S) composite, utilized as the Li–S battery cathode, delivers a high discharge capacity of 1313.4 mA h g−1 at 0.1C, glorious rate performance with 671.6 mA h g−1 at 2.0C and remarkable cycling stability with a capacity fading rate of 0.059% per cycle for 500 cycles at 1.0C. This work provides a novel and simple strategy to design a CNT decorated polar and conductive hybrid network of doped porous carbon/transition metal sulfide for application in excellent performance Li–S batteries and numerous energy storage fields.