Nitrogen-doped carbon nanofiber webs (CNFWs) with high surface areas are successfully prepared by carbonization-activation of polypyrrole nanofiber webs with KOH. The as-obtained CNFWs exhibit a superhigh reversible capacity of 943 mAh g(-1) at a current density of 2 A g(-1) even after 600 cycles, which is ascribed to the novel porous nanostructure and high-level nitrogen doping.

Nitrogen‐Doped Porous Carbon Nanofiber Webs as Anodes for Lithium Ion Batteries with a Superhigh Capacity and Rate Capability

Heteroatom doped carbon materials represent one of the most prominent families of materials that are used in energy related applications, such as fuel cells, batteries, hydrogen storage or supercapacitors. While doping carbons with nitrogen atoms has experienced great progress throughout the past decades and yielded promising material concepts, also other doping candidates have gained the researchers' interest in the last few years. Boron is already relatively widely studied, and as its electronic situation is contrary to the one of nitrogen, codoping carbons with both heteroatoms can probably create synergistic effects. Sulphur and phosphorus have just recently entered the world of carbon synthesis, but already the first studies published prove their potential, especially as electrocatalysts in the cathodic compartment of fuel cells. Due to their size and their electronegativity being lower than those of carbon, structural distortions and changes of the charge densities are induced in the carbon materials. This article is to give a state of the art update on the most recent developments concerning the advanced heteroatom doping of carbon that goes beyond nitrogen. Doped carbon materials and their applications in energy devices are discussed with respect to their boron-, sulphur- and phosphorus-doping.

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Doping carbons beyond nitrogen: an overview of advanced heteroatom doped carbons with boron, sulphur and phosphorus for energy applications

Reversibly intercalating ions into host materials for electrochemical energy storage is the essence of the working principle of rocking-chair type batteries. The most relevant example is the graphite anode for rechargeable Li-ion batteries which has been commercialized in 1991 and still represents the benchmark anode in Li-ion batteries 30 years later. Learning from past lessons on alkali metal intercalation in graphite, recent breakthroughs in sodium and potassium intercalation in graphite have been demonstrated for Na-ion batteries and K-ion batteries. Interestingly, some significant differences proved to exist for the intercalation of Na+ and K+ into graphite compared with the Li+ case. Such different host-guest interactions are unique depending on the host materials and electrolytes, which greatly contribute to a deeper understanding of intercalation-type electrode materials for next generation alkali metal ion batteries. This review summarizes significant advances from both experimental and theoretical calculations with a focus on comparing the intercalation of three alkali metal ions (Li+, Na+, K+) into graphite and aims to clarify the intimate host-guest relationships and the underlying mechanisms. New approaches developed to achieve favorable intercalation coupled with the challenges in this field are also discussed. We also extrapolate alkali metal ion intercalation in graphite to mono-/multi-valent ions in layered electrode materials, which will deepen the understanding of intercalation chemistry and provide guidance to explore new guests and hosts.

Intercalation chemistry of graphite: alkali metal ions and beyond.

Nitrogen-enriched mesoporous carbons with tunable nitrogen content and similar mesoporous structures have been prepared by a facile colloid silica nanocasting to house sulfur for lithium–sulfur batteries. The results give unequivocal proof that nitrogen doping could assist mesoporous carbon to suppress the shuttling phenomenon, possibly via an enhanced surface interaction between the basic nitrogen functionalities and polysulfide species. However, nitrogen doping only within an appropriate level can improve the electronic conductivity of the carbon matrix. Thus, the dependence of total electrochemical performance on the nitrogen content is nonmonotone. At an optimal nitrogen content of 8.1 wt %, the carbon/sulfur composites deliver a highest reversible discharge capacity of 758 mA h g–1 at a 0.2 C rate and 620 mA h g–1 at a 1 C rate after 100 cycles. Furthermore, with the assistance of PPy/PEG hybrid coating, the composites could further increase the reversible capacity to 891 mA h g–1 after 100 cycles. T...

High Efficiency Immobilization of Sulfur on Nitrogen-Enriched Mesoporous Carbons for Li–S Batteries

Functionalized N-doped porous carbon nanofiber webs/sulfur (N-PCNF/S) composites are first proposed as the cathode materials for an advanced lithium–sulfur battery. The functionalized N-doped porous carbon nanofiber webs (N-PCNF) with an appropriate N doping (4.32 wt %) are synthesized by a facile approach, which consists of pyrolyzation of polypyrrole nanofiber and a subsequent KOH activation. Instrumental analysis shows that N-PCNF possesses a large specific surface area (2642 m2 g–1) and a high inner pore volume (1.31 cm3 g–1). When evaluating its electrochemical properties in a lithium–sulfur battery, the N-PCNF/S composite with 77.01 wt % sulfur content displays an excellent electrochemical performance. The specific discharge capacity still reaches 749.8 mAh g–1 after 180 cycles at 0.2 C. At a higher rate of 1 C, the capacity stabilizes at 666.0 mAh g–1 after 200 cycles. This work demonstrates that combining the favorable aspects of N doping modification and one-dimensional nanostructure in the carbo...

Functionalized N-Doped Porous Carbon Nanofiber Webs for a Lithium–Sulfur Battery with High Capacity and Rate Performance

Graphitized boron-doped carbon foams: Performance as anodes in lithium-ion batteries

https://digital.csic.es/bitstream/10261/170940/1/Low-cost_carbon%20_foams_Rodriguez.pdf

Low-cost hierarchical micro/macroporous carbon foams as efficient sorbents for CO2 capture

Carbon materials loaded with maghemite as regenerable sorbents for gaseous Hg0 removal

http://digital.csic.es/bitstream/10261/104730/1/Characterization_boron_Rodriguez.pdf

Elena Rodríguez

Papers

Graphitized boron-doped carbon foams: Performance as anodes in lithium-ion batteries

Low-cost hierarchical micro/macroporous carbon foams as efficient sorbents for CO2 capture

Carbon materials loaded with maghemite as regenerable sorbents for gaseous Hg0 removal

Characterisation of boron-doped coal-derived carbon foams and their oxidation behaviour

Graphitic carbon foams as anodes for sodium-ion batteries in glyme-based electrolytes