Search

The exploration of preparing hierarchically porous carbons with adjustable pore structure from renewable biomass has attracted increasing attention by researchers. In this paper, the hierarchically porous carbon with excellent electrochemical properties is synthesized using renewable sodium alginate as a carbon source by in-situ pyrolysis of 'egg-box' structure with the addition of thiourea. The type/concentration of template resources and the thiourea additive have an important influence on the regulation of pore structure and the content of heteroatom here. More importantly, the doping of graphitic-N is conducive to enhancing the cycle stability of the electrode material. The PCNS–Zn sample has the most outstanding electrochemical performance with the high specific capacitance of 350 F g−1 at 1 A g−1 and the good rate capability of 82% capacitance retention at 50 A g−1. In addition, PCNS–Zn electrode shows a prominent cycle life with the capacitance retention rate of 90.4% at 5 A g−1 after 5000 cycles. From the perspective of sustainability, low cost and easy operation, this scheme has a broad development prospect for preparing porous carbon with controllable pore structure. • Porous carbons have been prepared by assembling of alginate and divalent cationic. • The template sources have an influence on the pore structure and nitrogen species. • Thiourea could regulate the size of template nano particles. • The doping of graphitic-N is conducive to enhance the cycle stability. [ABSTRACT FROM AUTHOR]

The exploration of preparing hierarchically porous carbons with adjustable pore structure from renewable biomass has attracted increasing attention by researchers. In this paper, the hierarchically porous carbon with excellent electrochemical properties is synthesized using renewable sodium alginate as a carbon source by in-situ pyrolysis of 'egg-box' structure with the addition of thiourea. The type/concentration of template resources and the thiourea additive have an important influence on the regulation of pore structure and the content of heteroatom here. More importantly, the doping of graphitic-N is conducive to enhancing the cycle stability of the electrode material. The PCNS–Zn sample has the most outstanding electrochemical performance with the high specific capacitance of 350 F g−1 at 1 A g−1 and the good rate capability of 82% capacitance retention at 50 A g−1. In addition, PCNS–Zn electrode shows a prominent cycle life with the capacitance retention rate of 90.4% at 5 A g−1 after 5000 cycles. From the perspective of sustainability, low cost and easy operation, this scheme has a broad development prospect for preparing porous carbon with controllable pore structure. • Porous carbons have been prepared by assembling of alginate and divalent cationic. • The template sources have an influence on the pore structure and nitrogen species. • Thiourea could regulate the size of template nano particles. • The doping of graphitic-N is conducive to enhance the cycle stability. [ABSTRACT FROM AUTHOR]

• FeS nanoparticles embedded in N -doped porous C is prepared by one-step strategy. • The N -doped C can improve conductivity, introduce defects and more active sites. • The FeS/NC electrode displays superior lithium-ion storage performance. • The electrochemical reaction mechanism is studied by ex-situ XPS. The electrode materials with simple preparation methods, good electrochemical performance, and cheap cost have broad application prospects in the field of electrochemistry. Herein, we propose one-step method for the direct sulfuration of iron-phthalocyanine (FePc) to produce FeS nanoparticles embedded in nitrogen-doped porous carbon (FeS/NC). Introducing porous carbon materials into the FeS nanoparticles can significantly restrain the huge volume expansion and enhance electrical conductivity. Nitrogen doping can further improve the electrical conductivity and introduce defects in the carbon host. The results show that the FeS/NC-750 demonstrates a discharge capacity of 834 mA h g−1after 100 cycles at 200 mA g−1. The FeS/NC anode still has a high discharge specific capacity of 612.4 mAh g−1 even after 500 cycles at 1000 mA g−1. The simple strategy provides an inexpensive and straightforward strategy for conversion of FePc into available FeS/NC anode materials, which presents that FeS/NC electrode has potential application value in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • N, S co-doped porous carbon/Sn composites are made by self-derived template method. • The synergistic effect of N, S co-doping is demonstrated by DFT calculations. • The Sn/NSPC anode yields a high discharge capacity of 712.6 mAh/g after 200 cycles. • Sn/NSPC full cell obtains a specific capacity of 572.6 mAh/g after 100 cycles. • The lithium storage mechanism is comprehensively revealed by in-situ XRD. Although single-heteroatom doped porous carbon/tin (Sn) composites have been extensively studied, an overall understanding of the effects of dual-heteroatoms doped porous carbon on the lithium storage properties of Sn is still insufficient. Herein, we provide a green self-derived templating strategy to synthesize the nitrogen, sulfur co-doped porous carbon/Sn composites (Sn/NSPC) with synergistic effect through one-step carbonization. The key to this approach is the self-generation of Na 2 CO 3 template, and it is apt to eliminate with water directly. The resultant NSPC can prevent the agglomeration of Sn particles. The synergistic effect is confirmed by density functional theoretical (DFT) calculations, revealing that N, S co-doped improves the electronic conductivity. The lithium storage mechanism and structural stability of Sn/NSPC electrode are researched via in-situ XRD and ex-situ XPS. The obtained electrode affords a discharge capacity (200 cycles, 712.6 mAh/g at 0.1 A/g) and long-life cyclability (2000 cycles, 330.1 mAh/g at 3 A/g). Additionally, the Sn/NSPC||LiCoO 2 full cell achieves excellent discharge capacity (572.6 mAh/g at 0.1 A/g) while remaining impressive cyclability (440.6 mAh/g at 1 A/g). This green and eco-friendly approach may be extended to the preparation of other heteroatom-doped carbon/Sn composites. [ABSTRACT FROM AUTHOR]