Nanocomposites that combine porous materials and a continuous conductive skeleton as a sulfur host can improve the performance of lithium–sulfur (Li-S) batteries. Herein, carbon nanotubes (CNTs) anchoring small-size (~40 nm) N-doped porous carbon polyhedrons (S-NCPs/CNTs) are designed and synthesized via annealing the precursor of zeolitic imidazolate framework-8 grown in situ on CNTs (ZIF-8/CNTs). In the nanocomposite, the S-NCPs serve as an efficient host for immobilizing polysulfides through physical adsorption and chemical bonding, while the interleaved CNT networks offer an efficient charge transport environment. Moreover, the S-NCP/CNT composite with great features of a large specific surface area, high pore volume, and short electronic/ion diffusion depth not only demonstrates a high trapping capacity for soluble lithium polysulfides but also offers an efficient charge/mass transport environment, and an effective buffering of volume changes during charge and discharge. As a result, the Li-S batteries based on a S/S-NCP/CNT cathode deliver a high initial capacity of 1213.8 mAh g⁻¹ at a current rate of 0.2 C and a substantial capacity of 1114.2 mAh g⁻¹ after 100 cycles, corresponding to a high-capacity retention of 91.7%. This approach provides a practical research direction for the design of MOF-derived carbon materials in the application of high-performance Li–S batteries.

Lithium–sulfur batteries (LSBs) have attracted widespread attention due to their high theoretical energy density and low cost. However, their development has been constrained by the shuttle effect of lithium polysulfides and their slow reaction kinetics. In this work, a nitrogen/oxygen dual-doped porous carbon (N/O-PC) was synthesized by annealing the precursor of zeolitic imidazolate framework-8 grown in situ on MWCNTs (ZIF-8/MWCNTs). Then, the N/O-PC composite served as an efficient host for LSBs through chemical adsorption and providing catalytic conversion sites of polysulfides. Moreover, the interconnected porous carbon-based structure facilitates electron and ion transfer. Thus, the S/N/O-PC cathode exhibits high cycling stability (a stable capacity of 685.9 mA h g⁻¹ at 0.2 C after 100 cycles). It also demonstrates excellent rate performance with discharge capacities of 1018.2, 890.2, 775.1, 722.7, 640.4, and 579.6 mAh g⁻¹ at 0.2, 0.5, 1.0, 2.0, 3.0, and 5.0 C, respectively. This work provides an effective strategy for designing and developing high energy density, long cycle life LSBs.

Lithium–selenium batteries (LSeBs) have potential applications in mobile electronic devices and electric vehicles due to their high theoretical volume specific capacity (3253 mAh cm⁻³). However, their cycling performance is poor because of the serve shuttle effect. Porous carbon can restrict the shuttle effect. However, past porous carbon is cumbersome, expensive, and unsuitable for large-scale production. In this work, we develop an annealing/etching method to convert biowaste (Rapeseed meal) to a N, S co-doped three-dimensional porous carbon (NSPC) which is then used as the Se host for LSeBs. The Se/NSPC composite delivers a specific capacity of 496.5 mAh g⁻¹ for 200 cycles at 0.2 C, corresponding to a high-capacity retention of 91.8%. Moreover, the Se/NSPC composite maintains a high capacity over 200 mAh g⁻¹ after 1000 cycles at a high current density of 2 C. Our work provides an efficient approach to addressing biowaste issues while simultaneously facilitating the mass production of economical Se hosts for LSeBs.