Porous carbon nanofibers as anode for high-performance potassium-ion batteries

Synthesis of nitrogen-doped amorphous carbon nanotubes from novel cobalt-based MOF precursors for improving potassium-ion storage capability

Amorphous carbon materials with sophisticated morphologies, variable carbon layer structures, abundant defects, and tunable porosities are favorable as anodes for potassium-ion batteries (PIBs). Synthesizing amorphous carbon materials typically involves the pyrolysis of carbonaceous precursors. Nonetheless, there is still a lack of studies focused on achieving multifaceted structural optimizations of amorphous carbon through precursor formulation. Herein, nitrogen-doped amorphous carbon nanotubes (NACNTs) are derived from a novel composite precursor of cobalt-based metal-organic framework (CMOF) and graphitic carbon nitride (g-CN). The addition of g-CN in the precursor optimizes the structure of amorphous carbon such as morphology, interlayer spacing, nitrogen doping, and porosity. As a result, NACNTs demonstrate significantly improved electrochemical performance. The specific capacities of NACNTs after cycling at current densities of 100 mA/g and 1000 mA/g increased by 194 % and 230 %, reaching 346.6 mAh/g and 211.8 mAh/g, respectively. Furthermore, the NACNTs anode is matched with an organic cathode for full-cell evaluation. The full-cell attains a high specific capacity of 106 mAh/gcathode at a current density of 100 mA/g, retaining 90.5 % of the specific capacity of the cathode half-cell. This study provides a valuable reference for multifaceted structural optimization of amorphous carbon to improve potassium-ion storage capability.

Advances in porous carbon materials for a sustainable future: A review

Developing clean and renewable energy sources is key to a sustainable future. For human society to progress sustainably, environmentally friendly energy conversion and storage technologies are critical. The use of nanostructured advanced functional materials heavily influences the functionality of these systems. Porous carbons are multifunctional materials boasting considerable industrial utility. They possess many remarkable physiochemical and mechanical characteristics which have garnered interest in various fields. In this review, the application of porous carbon materials in electrocatalysis (HER, OER, ORR, NARR, and CO2RR) and rechargeable batteries (LIBs, LiS batteries, NIBs, and KIBs) for renewable energy conversion and storage are discussed. The suitability of porous carbon materials for these applications is discussed, and some recent works are reviewed. Finally, a few viewpoints on developing porous carbons in electrocatalysis and rechargeable batteries are given. This review aims to generate interest in current and upcoming researchers in porous carbon application for a sustainable future.

Advancements and Prospects of Graphite Anode for Potassium-Ion Batteries

Potassium-ion batteries (KIBs) have recently attracted considerable attention owing to their resource abundance, low cost and environmental friendliness. Graphite as a mature commercial anode material for lithium-ion batteries, has been proved as a promising anode candidate for KIBs by reversible forming potassium-graphite intercalation compounds. However, large volume expansion and sluggish K+ kinetics caused by the incompatibility between large radius of K+ and the small interlayer spacing of graphite, result in the poor cycle stability and rate performances, hindering its practical application. Extensive research efforts have focused on improving the potassium storage performance of graphite anodes. This review provides an overview of recent advances in addressing these challenges and optimizing the electrochemical performance of graphite anodes for KIBs. Various strategies to improve the electrochemical performance of graphite and graphitic carbon anodes, such as microcrystalline regulation, heteroatom doping, morphological adjustment, and coating modification, are discussed, while the critical issues and challenges associated with graphite anodes and the prospects for their advancement in KIBs are highlighted. The review offers valuable guidelines for rational structural design and promotes the commercial development of high-performance graphite anode materials for KIBs.

Carbon nanosphere synthesis and applications for rechargeable batteries

Carbon nanospheres (CNSs) have attracted great interest in energy conversion and storage technologies due to their excellent chemical and thermal stability, high electrical conductivity and controllable size structure characteristics. In order to further improve the energy storage properties, many efforts have been made to design suitable nanocarbon spherical materials to improve electrochemical performance. In this overview, we summarize the recent research progress on CNSs, mainly focusing on the synthesis methods and their application as high-performance electrode materials in rechargeable batteries. As for the synthesis methods, hard template methods, soft template methods, the extension of the Stöber method, hydrothermal carbonization, aerosol-assisted synthesis are described in detail. In addition, the use of CNSs as electrodes in energy storage devices (mainly concentrated on lithium-ion batteries (LIBs)), sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) are also discussed in detail in this article. Finally, some perspectives on the future research and development of CNSs are provided.

Air-stabilized pore structure engineering of antimony-based anode by electrospinning for potassium ion batteries

Due to the large ionic radius and associated slow reaction kinetics of potassium ions, it is a major challenge to find suitable anode materials for potassium-ion batteries. Herein, we design porous antimony-based nanofibres via a simple, low-cost and large scalable method to promote the electrochemical performance of potassium-ion batteries. Unlike those traditionally treated in inert atmospheres, using the different decomposition processes of polyacrylonitrile and polyvinylpyrrolidone in air, we obtain antimony trioxide embedded in porous carbon nanofibres (Sb₂O₃@PCN). The porous structure can promote the permeation of electrolyte into electrode materials and increase the active sites of the redox reaction. The porous carbonaceous fibre skeleton structure establishes a fast ion transport channel and enhances the kinetic performance. In a concentrated 5 M potassium bis(fluorosulfonyl)-imide/dimethyl carbonate electrolyte, Sb₂O₃@PCN exhibits a stable discharge specific capacity of 437.3 mAh g^-1 at a current density of 100 mA g^-1 after 50 cycles, which is much higher than that treated in a N₂ atmosphere (247.5 mAh g^-1). This method provides a new approach for the preparation of efficient potassium-ion battery electrode materials.

Carbon-Based Modification Materials for Lithium-ion Battery Cathodes: Advances and Perspectives

Lithium-ion batteries (LIBs) have attracted great attention as an advanced power source and energy-storage device for years due to their high energy densities. With rapid growing demands for large reversible capacity, high safety, and long-period stability of LIBs, more explorations have been focused on the development of high-performance cathode materials in recent decades. Carbon-based materials are one of the most promising cathode modification materials for LIBs due to their high electrical conductivity, large surface area, and structural mechanical stability. This feature review systematically outlines the significant advances of carbon-based materials for LIBs. The commonly used synthetic methods and recent research advances of cathode materials with carbon coatings are first represented. Then, the recent achievements and challenges of carbon-based materials in LiCoO2, LiNixCoyAl1-x-yO2, and LiFePO4 cathode materials are summarized. In addition, the influence of different carbon-based nanostructures, including CNT-based networks and graphene-based architectures, on the performance of cathode materials is also discussed. Finally, we summarize the challenges and perspectives of carbon-based materials on the cathode material design for LIBs.