New Carbon Materials最新文献

The use of lithium-ion batteries (LIBs) is becoming increasingly widespread, and a large number are reaching their end of life. The recycling and re-use of spent LIBs has attracted great attention. Because of the unchanged layer structure of the graphite anode in these batteries, their recycling does not require high-temperature graphitization, and only focuses on the removal of internal impurities. We used electrochemical treatment for the deep removal of internal metal impurities after the heat treatment, ultrasonic separation, and acid leaching of spent graphite. By comparing and analyzing the graphite in different recovery stages, it was found that the presence of organic impurities seriously affects the electrochemical performance. The presence of trace inorganic impurities such as Cu and Fe has little effect on the initial discharge specific capacity, but reduces the cycling stability of graphite. The content of the main metal impurities in the final recycled graphite was less than 20 mg/kg. The discharge specific capacity reached358.7 mAh/g at 0.1 C, and the capacity remained at 95.85% after 150 cycles. Compared with the reported methods for recycling spent graphite, this method can efficiently remove impurities in the graphite, solve the current problems of high acid and alkali consumption, incomplete impurity removal and high energy consumption. The recycled graphite anode has a good electrochemical performance. Our work provides a new recycling and regeneration path for spent LIB graphite anodes.

Capacitive deionization has been considered an emerging desalination technique in recent years, especially for its economic and energy-saving characteristics for brackish water. However, there are currently few studies on chloride ion removal electrodes, and the slow desalination kinetics limits their development. Ar-NiCoAl- layered double hydroxide (LDH)@ACC materials with an increased interlayer spacing were prepared by the in-situ growth of NiCoAl-LDHs nanosheet arrays on acid-treated carbon cloth (ACC) and subsequent Ar plasma treatment. The carbon cloth suppresses the agglomeration of the NiCoAl-LDHs nanosheets and improves the electrical conductivity, while the plasma treatment increases the interlayer spacing of NiCoAl-LDHs and improves its hydrophilicity. This provides rapid diffusion channels and more interlayer active sites for chloride ions, achieving high desalination kinetics. A hybrid capacitive deionization (HCDI) cell was assembled using Ar-NiCoAl-LDHs@ACC as the chloride ion removal electrode and activated carbon as the sodium ion removal electrode. This HCDI cell achieved a high desalination capacity of 93.26 mg g⁻¹ at 1.2 V in a 1000 mg L⁻¹ NaCl solution, a remarkable desalination rate of 0.27 mg g⁻¹ s⁻¹, and a good charge efficiency of 0.97. The capacity retention remained above 85% after 100 cycles in a 300 mg L⁻¹ NaCl solution at 0.8 V. The work provides new ideas for the controlled preparation of two-dimensional metal hydroxide materials with a large interlayer spacing and the design of high-performance electrochemical chlorine ion removal electrodes.

Graphdiyne is a novel carbon material with a special carbon hybrid arrangement, unique chemical and electronic structure and numerous pores that has promising applications in electrochemical energy storage. Emerging aqueous ion batteries have advantages of low cost and high safety, but the development of high-performance electrode materials, the design of new membrane systems and ways of stabilizing the interface remain the main challenges in their manufacture. With its unique porous structure and excellent electrochemical properties, graphdiyne can improve ion transport, interface deposition behavior and electrolyte instability in the aspects of anode protection, cathode cladding, membrane design and stabilizing the pH value of the interface. A bottom-up molecular structural design strategy makes graphdiyne easy to modify and dope, improving the properties of its analogues and thus expanding their applications in aqueous ion batteries. We systematically summarize the structure, properties, and synthesis methods of graphdiyne, and summarize the research of graphdiyne in aqueous ion batteries. A comprehensive evaluation of the existing problems and challenges of the use of graphdiyne in aqueous ion batteries is given, and future trends and developments are suggested.

Metal chloride-intercalated graphite with excellent conductivity and a large interlayer spacing is highly desired for use in sodium ion batteries. However, halogen vapor is usually indispensable in initiating the intercalation process, which makes equipment design and experiments challenging. In this work, SO₂Cl₂ was used as a chlorine generator to intensify the intercalation of BiCl₃ into graphite (BiCl₃-GICs), which avoided the potential risks, such as Cl₂ leakage, in traditional methods. The operational efficiency in the experiment was also improved. After the reaction of SO₂Cl₂, BiCl₃, and graphite at 200 ^oC for 20 h, the synthesized BiCl₃-GICs had a large interlayer spacing (1.26 nm) and a high amount of BiCl₃ intercalation (42%), which gave SIBs a high specific capacity of 213 mAh g⁻¹ at 1 A g⁻¹ and an excellent rate performance (170 mAh g⁻¹ at 5 A g⁻¹). In-situ Raman spectra revealed that the electronic interaction between graphite and intercalated BiCl₃ is weakened during the first discharge, which is favorable for sodium storage. This work broadly enables the increased intercalation of other metal chloride-intercalated graphites, offering possibilities for developing advanced energy storage devices.

Graphene is widely used in photodetection because of its high carrier mobility and wide spectral absorption range. However, its high dark current caused by its low light absorption severely limits its performance. Molybdenum dihalide (MoX₂, X= S, Se and Te) has a high absorption coefficient, which can compensate for the high dark current in graphene-based photodetectors and result in outstanding photoelectronic properties of those based on a graphene/MoX₂ van der Waals heterostructure (vdWH). In this review, we firstly review working principles, performance indicators, and structures of photodetectors. After that, the significance of graphene/MoX₂vdWH photodetectors is highlighted from the fundamental perspective. Preparation methodologies and performance enhancement strategies of graphene/MoX₂vdWH photodetectors are correspondingly summarized. In the end, we highlight the current challenges and future directions of the graphene/MoX₂vdWH photodetectors. This review will guide the design of high-performance vdWH photodetectors.

The electrocatalytic CO₂ reduction reaction (CO₂RR) is an environmentally friendly way to convert CO₂ into valuable chemicals. However, CO₂ conversion is a complex process, which contains 2, 4, 6, 8 and 12 electron transfer processes. It is very important to develop efficient catalysts to precisely control the number of electron transfers for the chemicals required. Single-metal catalysts have some deficiencies, including slow reaction kinetics, low product selectivity and inadequate stability. In response to these challenges, bimetallic catalysts have received significant attention owing to their unique structure and improved performance. The introduction of secondary metals alters the catalyst’s electronic structure, and creates novel active sites, as well as optimizing their interaction with the intermediates. This review provides a comprehensive account of atomically distributed bimetals based on carbon materials and non-atomic distributed bimetals such as alloys and heterostructures, including their synthesis methods, characterization, and the outcomes of different catalysts. Catalytic mechanisms of different bimetallic catalysts are proposed and challenges encountered in the CO₂RR are considered.

Exploring cost-efficient and highly-efficient noble metal-free catalysts for the oxygen reduction reactions (ORRs) involved in sustainable energy devices remains a great challenge. Transition-metal phosphides supported on heteroatom-doped carbons have shown potential as alternative candidates for precious metals because of their tunable electronic structures and higher catalytic performance. Phosphating was used to construct CoP nanoparticles (NPs) anchored on a nitrogen-doped porous carbon framework (CoP@NC) from Co NPs loaded on NC, using PH₃ gas released from NaH₂PO₂ during heat treatment. The dodecahedral structure of Co NPs was retained in their transformation to CoP NPs. The CoP@NC electrocatalyst shows a remarkable ORR activity with a half-wave potential up to 0.92 V under alkaline conditions, which is attributed to the combined coupling between the well dispersed CoP nanoparticles on the nitrogen-doped carbon and the efficient mass transport in the porous structure. Zinc-air batteries assembled with the CoP@NC electrocatalyst as a cathode have a high open-circuit voltage of 1.51 V and power density of 210.1 mW cm⁻². This work provides a novel strategy to develop low-cost catalysts with an excellent ORR performance to promote their practical use in metal-air batteries

Recent advances in the use of carbon-supported single-atom catalysts (SACs) for electrochemical reactions are comprehensively reviewed. The development and advantages of carbon-supported SACs are briefly introduced, followed by a detailed summary of the synthesis strategies used, including vapor phase transport, high temperature pyrolysis and wet chemical methods. Advanced characterization techniques for carbon-supported SACs are also reviewed. The use of carbon-supported SACs in different fields, such as the oxygen reduction reaction, carbon dioxide reduction reaction, nitrogen reduction reaction, hydrogen evolution reaction, and oxygen evolution reaction are summarized. Special emphasis is given to the modification strategies used to enable carbon-supported SACs to have an excellent electrocatalytic performance. Finally, the prospects and challenges associated with using carbon-supported SACs for electrochemical reactions are discussed.

In recent years, zinc-ion hybrid capacitors (ZIHCs) have attracted increasing attention due to their environmental friendliness and excellent electrochemical properties. However, their performance is mainly limited by the electrochemical performance of the cathode, so it is necessary to develop an advanced cathode material. N, B co-doped sodium alginate-based porous carbon (NBSPC) was prepared by one-step co-carbonization using sodium alginate as the matrix and NH₄B₅O₈ as the N and B source. This N, B co-doping strategy improves the pore structure of the carbon materials and increases the number of surface functional groups, greatly improving the capacitive behavior of the raw materials and thus improving their electrochemical performance. When used as the cathode in ZIHCs, the NBSPC had an excellent rate performance (85.4 mAh g⁻¹ even at ultra-high current density of 40 A g⁻¹) and good cycling stability (15 000 cycles at 20 A g⁻¹ with a capacity retention rate of 94.5%).

Carbon materials, including carbon nanotubes/nanofibers, graphene, graphene oxide, reduced graphene oxide, graphyne, graphdiyne, carbon quantum dots and fullerenes, have received considerable attention in recent years because of their unique properties such as high conductivity, excellent stability and biocompatibility. The integration of these materials into Z-scheme and S-scheme heterojunctions has emerged as a transformative strategy to increase their photocatalytic efficiency for energy conversion applications. We first consider the fundamental principles of clean energy generation such as photocatalytic H₂ generation and CO₂ reduction, elucidating their respective mechanisms and advantages. Various types of carbon materials, their synthesis and construction of Z-scheme and S-scheme heterojunctions are then discussed, emphasizing their role in promoting charge separation, reducing recombination losses and extending the spectral response range. With a focus on solar energy production, recent advances in carbon-based Z-scheme and S-scheme heterojunctions are discussed and summarized for photocatalytic H₂ generation and CO₂ reduction. Lastly, the current problems in the field of carbon-based photocatalysts are discussed with insights for the future development of this field.