Nitrogen and boron doped carbon layer coated multiwall carbon nanotubes as high performance anode materials for lithium ion batteries

Sodium Storage Properties of Carbonaceous Flowers

As a promising energy storage system, sodium-ion batteries face challenges related to the stability and high-rate capability of their electrode materials, especially carbon, which is the most studied anode. Previous studies have demonstrated that three-dimensional architectures composed of porous carbon materials with high electrical conductivity have the potential to enhance the storage performance of sodium-ion batteries. Here, high-level N/O heteroatoms-doped carbonaceous flowers with hierarchical pore architecture are synthesized through the direct pyrolysis of homemade bipyridine-coordinated polymers. The carbonaceous flowers could provide effective transport pathways for electrons/ions, thus allowing for extraordinary storage properties in sodium-ion batteries. As a consequence, sodium-ion battery anodes made of carbonaceous flowers exhibit outstanding electrochemical features, such as high reversible capacity (329 mAh g^-1 at 30 mA g^-1), superior rate capability (94 mAh g^-1 at 5000 mA g^-1), and ultralong cycle lifetimes (capacity retention rate of 89.4% after 1300 cycles at 200 mA g^-1). To better investigate the sodium insertion/extraction-related electrochemical processes, the cycled anodes are experimentally analyzed with scanning electron microscopy and transmission electron microscopy. The feasibility of the carbonaceous flowers as anode materials was further investigated using a commercial Na₃V₂(PO₄)₃ cathode for sodium-ion full batteries. All these findings indicate that carbonaceous flowers may possess great potential as advanced materials for next-generation energy storage applications.

Research on the utilization of ultra-long carbon nanotubes in lithium-ion batteries based on an environment-friendly society

To build an environment-friendly society, clean transportation systems, and renewable energy sources play essential roles. It is critical to improve the lifetime mileage of electric vehicles' batteries for reducing the cycle life cost and carbon footprint in green transportation. In this paper, a long-life lithium-ion battery is achieved by using ultra-long carbon nanotubes (UCNTs) as a conductive agent with relatively low content (up to 0.2% wt.%) in the electrode. Ultra-long CNT could realize longer conductive path crossing active material bulks in the electrode. Meanwhile, the low content of UCNTs can help to minimize conductive agent content in electrodes and obtain higher energy density. The film resistance and electrochemical impedance spectroscopy (EIS) confirmed that the use of UCNTs could markedly enhance electronic conductivity in the battery. The battery's life and life mileage can be prolonged by almost half due to the superior electronic conductivity of UCNTs. The life cycle cost and carbon footprint are also significantly reduced, which could markedly increase economic and environmental performance.

Biomass Alginate Derived Oxygen-Enriched Carbonaceous Materials with Partially Graphitic Nanolayers for High Performance Anodes in Lithium-Ion Batteries

Lithium-ion batteries with high reversible capacity, high-rate capability, and extended cycle life are vital for future consumer electronics and renewable energy storage. There is a great deal of interest in developing novel types of carbonaceous materials to boost lithium storage properties due to the inadequate properties of conventional graphite anodes. In this study, we describe a facile and low-cost approach for the synthesis of oxygen-doped hierarchically porous carbons with partially graphitic nanolayers (Alg-C) from pyrolyzed Na-alginate biopolymers without resorting to any kind of activation step. The obtained Alg-C samples were analyzed using various techniques, such as X-ray diffraction, Raman, X-ray photoelectron spectroscopy, scanning electron microscope, and transmission electron microscope, to determine their structure and morphology. When serving as lithium storage anodes, the as-prepared Alg-C electrodes have outstanding electrochemical features, such as a high-rate capability (120 mAh g^-1 at 3000 mA g^-1) and extended cycling lifetimes over 5000 cycles. The post-cycle morphologies ultimately provide evidence of the distinct structural characteristics of the Alg-C electrodes. These preliminary findings suggest that alginate-derived carbonaceous materials may have intensive potential for next-generation energy storage and other related applications.

Structural Characteristics and Electrochemical Performance of N,P-Codoped Porous Carbon as a Lithium-Ion Battery Anode Electrode

Biomass-derived heteroatom-doped carbons have been considered to be excellent lithium ion battery (LIB) anode materials. Herein, ultrathin g-C₃N₄ nanosheets anchored on N,P-codoped biomass-derived carbon (N,P@C) were successfully fabricated by carbonization in an argon atmosphere. The structural characteristics of the resultant N,P@C were elucidated by SEM, TEM, FTIR, XRD, XPS, Raman, and BET surface area measurements. The results show that N,P@C has a high specific surface area (S _BET = 675.4 cm³/g), a mesoporous-dominant pore (average pore size of 6.898 nm), and a high level of defects (I _D/I _G = 1.02). The hierarchical porous structural properties are responsible for the efficient electrochemical performance of N,P@C as an anode material, which exhibits an outstanding reversible specific capacity of 1264.3 mAh/g at 100 mA/g, an elegant rate capability of 261 mAh/g at 10 A, and a satisfactory cycling stability of 1463.8 mAh/g at 1 A after 500 cycles. Because of the special structure and synergistic contributions from N and P heteroatoms, the resultant N,P@C endows LIBs with electrochemical performance superior to those of most of carbon-based anode materials derived from biomass in the literature. The findings in this present work pave a novel avenue toward lignin volarization to produce anode material for use in high-performance LIBs.