A 3D Organically Synthesized Porous Carbon Material for Lithium-Ion Batteries

Atom-Economical Synthesis of Lewis Acidic Boron Containing Porous Organic Polymers via Hydroboration Polymerization for Basic Chemical Capture

Atom economy is one of the main concerns for material synthesis. Here, the facile synthesis of Lewis acidic boron-containing porous organic polymers (B-POPs) via hydroboration polymerization reaction of commercially available borane dimethyl sulfide complex (BH3∙SMe2) with multi-alkynes under mild reaction conditions is presented. This new synthetic method for B-POPs has the advantage of high atom economy. The resulted porous alkenyl borane polymers (PABPs) have unique features such as high boron content, strong Lewis acidity, and high surface areas. Owing to the strong Lewis acid-base interactions, PABPs exhibit excellent adsorptive capacity toward triethylamine (up to 841 mg g-1) and pyridine (up to 1396 mg g-1) vapor.

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.

Facile Synthesis of Organically Synthesized Porous Carbon Using a Commercially Available Route with Exceptional Electrochemical Performance

Organically synthesized porous carbon (OSPC) is a subclass of conjugated microporous polymer materials that have shown potential applications as anodes in ion batteries. However, a challenging, low-yielding, multistep synthetic route (the A method) has hindered further exploration of this exciting family. Here, OSPC-1 has been synthesized via an alternative, efficient one-pot method from commercially available reagents (the B method), hereafter referred to as OSPC-1b in contrast to OSPC-1a, where it is synthesized via the A method. Characterization revealed the same polymer structure and the highest surface area to date of an OSPC (or OSPC analogue) family member for OSPC-1b with 909 m2 g-1. OSPC-1b was tested as an anode for Li-ion batteries, demonstrating the same high capacity, fast charging, resistance to degradation, and inhibition of the formation of dangerous lithium dendrites as OSPC-1a. Furthermore, the electrochemical properties of OSPC-0 were evaluated for the first time, agreeing with previously predicted values, giving scope for the design and targeting of specific properties.

Crystallization-induced formation of two-dimensional carbon nanosheets derived from sodium lignosulfonate for fast lithium storage

Sodium lignosulfonate, an abundant natural resource, is regarded as an ideal precursor for the synthesis of hard carbon. The development of high-performance, low-cost and sustainable anode materials is a significant challenge facing lithium-ion batteries (LIBs). The modulation of morphology and defect structure during thermal transformation is crucial to improve Li+ storage behavior. Synthesized using sodium lignosulfonate as a precursor, two-dimensional carbon nanosheets with a high density of defects were produced. The synergistic influence of ice templates and KCl was leveraged, where the ice prevented clumping of potassium chloride during drying, and the latter served as a skeletal support during pyrolysis. This resulted in the formation of an interconnected two-dimensional nanosheet structure through the combined action of both templates. The optimized sample has a charging capacity of 712.4 mA h g-1 at 0.1 A g-1, which is contributed by the slope region. After 200 cycles at 0.2 A g-1, the specific charge capacity remains 514.4 mA h g-1, and a high specific charge capacity of 333.8 mA h g-1 after 800 cycles at 2 A g-1. The proposed investigation offers a promising approach for developing high-performance, low-cost carbon-based anode materials that could be used in advanced lithium-ion batteries.

Tailoring the Microstructure of Porous Carbon Spheres as High Rate Performance Anodes for Lithium-Ion Batteries

Benefiting from their high surface areas, excellent conductivity, and environmental-friendliness, porous carbon nanospheres (PCSs) are of particular attraction for the anodes of lithium-ion batteries (LIBs). However, the regulation of carbon nanospheres with controlled pore distribution and graphitization for delivering high Li⁺ storage behavior is still under investigation. Here, we provide a facile approach to obtain PCSs with different microstructures via modulating the carbonization temperatures. With the processing temperature of 850 °C, the optimized PCSs exhibit an increased surface area, electrical conductivity, and enhanced specific capacity (202 mA h g^-1 at 2 A g^-1) compared to the PCSs carbonized at lower temperatures. Additionally, PCSs 850 provide excellent cyclability with a capacity retention of 83% for 500 cycles. Such work can pave a new pathway to achieve carbon nanospheres with excellent performances in LIBs.

Photo-Modulating CO2 Uptake of Hypercross-linked Polymers Upcycled from Polystyrene Waste

Incorporating photo-switches into skeletal structures of microporous materials or as guest molecules yield photo-responsive materials for low-energy CO₂ capture but at the expense of lower CO₂ uptake. Here, we overcome this limitation by exploiting trans-cis photoisomerization of azobenzene loaded into the micropores of hypercross-linked polymers (HCPs) derived from waste polystyrene. Azobenzene in HCP pores reduced CO₂ uptake by 19 %, reaching 37.7 cm³  g^-1 , but this loss in CO₂ uptake was not only recovered by trans-cis photoisomerization of azobenzene, but also increased by 22 %, reaching 56.9 cm³  g^-1 , when compared to as-prepared HCPs. Computational simulations show that this increase in CO₂ uptake is due to photo-controlled increments in 10-20 Å micropore volume, i. e., adsorption sites and a photo-reversible positive dipole moment. Irradiating these HCPs with visual-range light reverted CO₂ uptake to 33 cm³  g^-1 . This shows that it is feasible to recycle waste polystyrene into advanced materials for low-energy carbon capture.

Uncovering the origin of the anomalously high capacity of a 3d anode via in situ magnetometry

Transition metals can deliver high lithium storage capacity, but the reason behind this remains elusive. Herein, the origin of this anomalous phenomenon is uncovered by in situ magnetometry taking metallic Co as a model system. It is revealed that the lithium storage in metallic Co undergoes a two-stage mechanism involving a spin-polarized electron injection to the 3d orbital of Co and subsequent electron transfer to the surrounding solid electrolyte interphase (SEI) at lower potentials. These effects create space charge zones for fast lithium storage on the electrode interface and boundaries with capacitive behavior. Therefore, the transition metal anode can enhance common intercalation or pseudocapacitive electrodes at high capacity while showing superior stability to existing conversion-type or alloying anodes. These findings pave the way for not only understanding the unusual lithium storage behavior of transition metals but also for engineering high-performance anodes with overall enhancement in capacity and long-term durability.

Synthesis of Crystalline Phosphine-Graphdiyne with Self-Adaptive p-π Conjugation

"Dynamic" behavior materials with high surface activity and the ability of chemical bond conversion are the frontier materials in the field of renewable energy. The outstanding feature of these materials is that they have adaptive electronic properties that external stimuli can adjust. An original discovery in a new crystalline two-dimensional phosphine-graphdiyne (P-GDY) material is described here. Although the p-π conjugation of most trivalent phosphorus π-systems is insignificant because of the pyramidal configuration, the lone pair electrons of phosphorus atoms participate strongly in the delocalization under the influence of the interlayer van der Waals forces in P-GDY. Due to the dynamically reversible nature of noncovalent interactions (p-π conjugation), P-GDY exhibits a specific adaptive behavior and realizes the responsive reversible transport of a lithium ion by regulating p-π interactions. Our findings would provide the potential to develop a new family of responsive materials with tunable structures.

Rational Construction of C@Sn/NSGr Composites as Enhanced Performance Anodes for Lithium Ion Batteries

As a potential anode material for lithium-ion batteries (LIBs), metal tin shows a high specific capacity. However, its inherent "volume effect" may easily turn tin-based electrode materials into powder and make them fall off in the cycle process, eventually leading to the reduction of the specific capacity, rate and cycle performance of the batteries. Considering the "volume effect" of tin, this study proposes to construct a carbon coating and three-dimensional graphene network to obtain a "double confinement" of metal tin, so as to improve the cycle and rate performance of the composite. This excellent construction can stabilize the tin and prevent its agglomeration during heat treatment and its pulverization during cycling, improving the electrochemical properties of tin-based composites. When the optimized composite material of C@Sn/NSGr-7.5 was used as an anode material in LIB, it maintained a specific capacity of about 667 mAh g^-1 after 150 cycles at the current density of 0.1 A g^-1 and exhibited a good cycle performance. It also displayed a good rate performance with a capability of 663 mAh g^-1, 516 mAh g^-1, 389 mAh g^-1, 290 mAh g^-1, 209 mAh g^-1 and 141 mAh g^-1 at 0.1 A g^-1, 0.2 A g^-1, 0.5 A g^-1, 1 A g^-1, 2 A g^-1 and 5 A g^-1, respectively. Furthermore, it delivered certain capacitance characteristics, which could improve the specific capacity of the battery. The above results showed that this is an effective method to obtain high-performance tin-based anode materials, which is of great significance for the development of new anode materials for LIBs.

Elucidating the Role of Rational Separator Microstructures in Guiding Dendrite Growth and Reviving Dead Li

Li metal has attracted considerable attention as the preferred anode material for high-energy batteries. However, Li dendrites have limited the development of Li-metal batteries. Herein, the effects of tuning the porous separator microstructure (SM) for guiding Li dendrite growth and reviving dead Li are revealed using a mechano-electrochemical phase-field model. A strategy of guiding, instead of suppression, was applied to avoid disordered Li dendrite growth. By analyzing the effects of the number of layers, thickness, degree of staggered overlap in the separator, interlayer spacing, and porosity of SM on Li dendrite behavior, we discovered that applying a rationally designed SM can finely guide the Li nucleation and growth direction toward dense deposition. The revival of dead Li was also observed via an in situ experiment on Li dendrites. The reactivation of dead Li after it recontacts Li metal was verified. These findings not only provide fundamental information for the tuning of the SM but can also help better understand the dendrite growth of other alkali metal-ion batteries.

High stability and high performance nitrogen doped carbon containers for lithium-ion batteries

For a long time, carbon has been an ideal material for various electrochemical energy storage devices and a key component in electrochemical energy storage systems due to its advantages of rich surface states, easy tenability, and good chemical stability. Stable and high-performance carbon materials can support future applications of high specific energy electrodes. Herein and for the first time, we have designed nitrogen-doped carbon hollow containers using oleylamine-coating TiO₂ mesocrystals as a precursor with a high specific surface area of 1231 m² g^-1. When applied as an anode for lithium-ion storage, a reversible capacity of 774.5 mA h g^-1 is obtained at a rate of 0.5 A g^-1 after 200 cycles. Meanwhile, at an even higher rate of 2 A g^-1, a capacity of 721.1 mA h g^-1 is still achieved after 500 cycles. Moreover, the carbon containers remain structurally intact after a series of cycles. This may be attributed to the nitrogen atoms doped on the carbon surface that can absorb multiple lithium ions and enhance the structural stability. These results provide technical support for the development of high specific energy electrode materials.

Molecular Design of 3D Porous Carbon Framework via One-Step Organic Synthesis

A new practical method for construction of 3D porous carbon was developed through molecular design via one-step synthesis from commercially available carbon tetrabromide and bis(trimethylsilyl)acetylene on a gram-scale, and the obtained porous carbon has a well-defined sp¹ -sp³ all-carbon structure (C₁₃ ), high stability, and high surface area.

Environmentally friendly automated line for recovering aluminium and lithium iron phosphate components of spent lithium-iron phosphate batteries

Lithium iron phosphate (LFP) batteries contain metals, toxic electrolytes, organic chemicals and plastics that can lead to serious safety and environmental problems when they are improperly disposed of. The published literature on recovering spent LFP batteries mainly focuses on policy-making and conceptual design. The production line of recovering spent LFP batteries and its detailed operation are rarely reported. A set of automatic line without negative impact to the environment for recycling spent LFP batteries at industrial scale was investigated in this study. It includes crushing, pneumatic separation, sieving, and poison gas treatment processes. The optimum retaining time of materials in the crusher is 3 minutes. The release rate is the highest when the load of the impact crusher is 800 g. An air current separator (ACS) was designed to separate LFP from aluminium (Al) foil and LFP powder mixture. Movement behaviour of LFP powder and Al foil in the ACS were analysed, and the optimized operation parameter (35.46 m/s) of air current speed was obtained through theoretical analysis and experiments. The weight contents of an Al foil powder collector from vibrating screen-3 and LFP powder collector from bag-type dust collector are approximately 38.7% and 52.4%, respectively. The economic cost of full manual dismantling is higher than the recovery production line. This recycling system provides a feasible method for recycling spent LFP batteries.

Engineering hollow carbon spheres: directly from solid resin spheres to porous hollow carbon spheres via air induced linker cleaving

Hollow carbon spheres (HCSs) have broad application in many fields such as catalysis, adsorption and energy storage. Due to various restrictions on hard and soft templates, self-templating methods have received extensive attention. Generally, the conventional self-templating method includes two steps, including the hollowing and carbonization process. Herein, a facile novel one-step air induced linker cleaving (AILC) method was developed to synthesize HCSs using 3-aminophenol formaldehyde (APF) resin spheres as the carbon precursor. In this case, the cavitation and carbonization processes occur simultaneously. The as-prepared HCSs were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and Raman spectroscopy. It was found that the cleavage of the ether bond groups (Ar-O-C) and the methylene (-CH₂) in the APF resulted in cavitation and carbonization. The degree of cavitation and carbonization can be adjusted by controlling the thermal treatment temperature and time in air. Furthermore, the sulfur cathode containing HCSs heated at 400 °C exhibited excellent electrochemical performance with an initial discharge capacity of 1006 mA h g^-1 at 0.2 C, and a low capacity decay rate of 0.097% per cycle over 500 cycles at 1 C. The novel one-step AILC strategy will pave a new avenue for the synthesis of hollow carbon spheres and their promising application in different areas.

High-efficiency adsorption of Cr(VI) and RhB by hierarchical porous carbon prepared from coal gangue

Coal gangue (CG) is one of the largest industrial solid wastes in the world produced during the process of coal mining. The accumulation of CG is easy to cause ion leakage, which is harmful to the environment and human body. The recovery and utilization of CG are imminent. In the process, a hierarchical porous carbon (HPC) adsorbent with excellent adsorption property for Cr(VI) and rhodamine B (RhB), was prepared from CG by a two-step method and characterized by SEM, TEM, XRD, XPS, TPD and BET. The results revealed that the specific surface area of HPC is up to 2012.7 m² g^-1, and its adsorption capacities for Cr(VI) and RhB are reached 320.51 and 3086.42 mg g^-1. The adsorption mechanism of RhB was the synergetic effect of physics and chemistry. While XPS results suggested that hierarchical porous carbons (HPCs) only have a chemisorption effect on Cr(VI). This study provided an idea for the preparation of HPCs from CG to remove inorganic and organic pollutants such as heavy metal Cr(VI) and RhB in water.

Vitreum Etching-Assisted Fabrication of Porous Hollow Carbon Architectures for Enhanced Capacitive Sodium and Potassium-Ion Storage

Carbonaceous materials exhibit promising application in electrochemical energy storage especially for hollow or porous structure due to the fascinating and outstanding properties. Although there has been achieved good progress, controllable synthesis of hollow or porous carbons with uniform morphology by a green and easy way is still a challenge. Herein, a new artful and green approach is designed to controllably prepare hollow porous carbon materials with the assistance of boron oxide vitreum under a relatively low temperature of 500 °C. The vitreous B₂ O₃ provides a flowing carbonization environment and acts as etching agent accompanying with boron doping. By this general strategy, hollow and porous carbon architectures with various morphology of spheres and hollow polyhedrons are successfully fabricated by metal organic framework (MOF) precursors. Furthermore, such hollow carbon materials exhibit considerably excellent Na⁺ /K⁺ storage properties through enhanced capacitive behavior due to due to the highly porous structure and large surface area. It is notable that hollow carbon spheres display nearly 90% initial Coulombic efficiency, outstanding rate capability with 130 mAh g^-1 at 30 A g^-1 and long cycling life for sodium ion storage.

Charging a Negatively Curved Nanographene and Its Covalent Network

This study explores a bottom-up approach toward negatively curved carbon allotropes from octabenzo[8]circulene, a negatively curved nanographene. Stepwise chemical reduction reactions of octabenzo[8]circulene with alkali metals lead to a unique highly reduced hydrocarbon pentaanion, which is revealed by X-ray crystallography suggesting a local view for the reduction and alkali metal intercalation processes of negatively curved carbon allotropes. Polymerization of the tetrabromo derivative of octabenzo[8]circulene by the nickel-mediated Yamamoto coupling reaction results in a new type of porous carbon-rich material, which consists of a covalent network of negatively curved nanographenes. It has a specific surface area of 732 m² g^-1 and functions as anode material for lithium ion batteries exhibiting a maximum capacity of 830 mAh·g^-1 at a current density of 100 mA·g^-1. These results indicate that this covalent network presents the key structural and functional features of negatively curved carbon allotropes.

Bridging Structural Inhomogeneity to Functionality: Pair Distribution Function Methods for Functional Materials Development

The correlation between structure and function lies at the heart of materials science and engineering. Especially, modern functional materials usually contain inhomogeneities at an atomic level, endowing them with interesting properties regarding electrons, phonons, and magnetic moments. Over the past few decades, many of the key developments in functional materials have been driven by the rapid advances in short-range crystallographic techniques. Among them, pair distribution function (PDF) technique, capable of utilizing the entire Bragg and diffuse scattering signals, stands out as a powerful tool for detecting local structure away from average. With the advent of synchrotron X-rays, spallation neutrons, and advanced computing power, the PDF can quantitatively encode a local structure and in turn guide atomic-scale engineering in the functional materials. Here, the PDF investigations in a range of functional materials are reviewed, including ferroelectrics/thermoelectrics, colossal magnetoresistance (CMR) magnets, high-temperature superconductors (HTSC), quantum dots (QDs), nano-catalysts, and energy storage materials, where the links between functions and structural inhomogeneities are prominent. For each application, a brief description of the structure-function coupling will be given, followed by selected cases of PDF investigations. Before that, an overview of the theory, methodology, and unique power of the PDF method will be also presented.

Sandwich shelled TiO2@Co3O4@Co3O4/C hollow spheres as anode materials for lithium ion batteries

A sandwich shelled hollow TiO₂@Co₃O₄@Co₃O₄/C composite is synthesized by consecutive coating of Co₃O₄ nanosheets and TiO₂ particles on Co₃O₄/C hollow spheres. The composite delivers an excellent lithium storage performance, maintaining 1081.78 mA h g^-1 after 100 cycles at 0.2 A g^-1 and 772.23 mA h g^-1 after 300 cycles at 1 A g^-1, due to its superior structure combining the advantages of each component with favorable electron-transfer, Li⁺-diffusion properties, and distinguished stability.

Rationalising the influence of solvent choice on the porosity of conjugated microporous polymers

Conjugated microporous polymers (CMPs) synthesised in different solvents give different surface areas dependent on the solvent choice. No one solvent results in a high surface area across a range of different CMP materials. Here, we present an investigation into how the porosity of CMPs is affected by solvent polarity. It is seen that the trends differ depending on the respective monomer dipole moments and whether hydrogen bonding groups are present in the monomers and are able to interact with the respective solvent via hydrogen bonding. It is believed that this methodology could be used to influence future materials design of both structure and synthesis strategy.

Cucurbit[6]uril-Derived Nitrogen-Doped Hierarchical Porous Carbon Confined in Graphene Network for Potassium-Ion Hybrid Capacitors

Potassium-ion hybrid capacitors (PIHCs) have attracted tremendous attention because their energy density is comparable to that of lithium-ion batteries, whose power density and cyclability are similar to those of supercapacitors. Herein, a pomegranate-like graphene-confined cucurbit[6]uril-derived nitrogen-doped carbon (CBC@G) with ultra-high nitrogen-doping level (15.5 at%) and unique supermesopore-macropores interconnected graphene network is synthesized. The carbonization mechanism of cucurbit[6]uril is verified by an in situ TG-IR technology. In a K half-cell configuration, CBC@G anode demonstrates a superior reversible capacity (349.1 mA h g-1 at 0.1 C) as well as outstanding rate capability and cyclability. Moreover, systematic in situ/ex situ characterizations, and theory calculations are carried out to reveal the origin of the superior electrochemical performances of CBC@G. Consequently, PIHCs constructed with CBC@G anode and KOH-activated cucurbit[6]uril-derived nitrogen-doped carbon cathode demonstrate ultra-high energy/power density (172 Wh kg-1/22 kW kg-1) and extraordinary cyclability (81.5% capacity retention for 5000 cycles at 5 A g-1). This work opens up a new application field for cucurbit[6]uril and provides an alternative avenue for the exploitation of high-performance PIHCs.

Q-Carbon: A New Carbon Allotrope with a Low Degree of s-p Orbital Hybridization and Its Nucleation Lithiation Process in Lithium-Ion Batteries

A novel metallic carbon allotrope, Q-carbon, was discovered using first-principles calculations. The named Q-carbon possessed a three-dimensional (3D) cage structure formed by carbon atoms with three ligands. The energy distribution of electrons in different orbitals revealed that Q-carbon has a low degree of s-p orbital hybridization. The calculated Li⁺ binding energies suggested Li⁺ aggregation inside Q-carbon during lithiation. As a result, a Li₈C₃₂ phase was formed and gradually expanded in Q-carbon, implying a typical two-phase transition. This allowed Q-carbon to have a constant theoretical voltage of 0.40 V, which effectively inhibited Li dendrite formation. A stable Li₈C₃₂/C₃₂ two-phase interface was confirmed by stress-strain analysis, and a calculated Li⁺ diffusion barrier of ∼0.50 eV ensured effective Li⁺ diffusion along a 3D pathway. This study was of great significance for the understanding of two-phase transition of Li⁺ storage materials and provided a new insight into the design of new carbon materials for energy storage applications.

Making Sense of Complex Carbon and Metal/Carbon Systems by Secondary Electron Hyperspectral Imaging

Carbon and carbon/metal systems with a multitude of functionalities are ubiquitous in new technologies but understanding on the nanoscale remains elusive due to their affinity for interaction with their environment and limitations in available characterization techniques. This paper introduces a spectroscopic technique and demonstrates its capacity to reveal chemical variations of carbon. The effectiveness of this approach is validated experimentally through spatially averaging spectroscopic techniques and using Monte Carlo modeling. Characteristic spectra shapes and peak positions for varying contributions of sp2-like or sp3-like bond types and amorphous hydrogenated carbon are reported under circumstances which might be observed on highly oriented pyrolytic graphite (HOPG) surfaces as a result of air or electron beam exposure. The spectral features identified above are then used to identify the different forms of carbon present within the metallic films deposited from reactive organometallic inks. While spectra for metals is obtained in dedicated surface science instrumentation, the complex relations between carbon and metal species is only revealed by secondary electron (SE) spectroscopy and SE hyperspectral imaging obtained in a state-of-the-art scanning electron microscope (SEM). This work reveals the inhomogeneous incorporation of carbon on the nanoscale but also uncovers a link between local orientation of metallic components and carbon form.

Facile and Scalable Fabrication of Nitrogen-Doped Porous Carbon Nanosheets for Capacitive Energy Storage with Ultrahigh Energy Density

Porous carbon materials are the most commonly used electrode materials for supercapacitors because of their abundant structures, excellent conductivities, and chemical stability. However, the manufacture of carbon materials possessing sizable pores and remarkable wettability with the electrolyte remains challenging. Herein, we developed a facile and industrially scalable method for the production of nitrogen-doped porous carbon nanosheets (PNDC-4) with excellent pore size distribution, large specific surface area (>1200 m² g^-1), high conductivity (>700 S m^-1), and superb wettability either in aqueous or organic electrolyte. Particularly, PNDC-4 shows a high capacitance of 387 F g^-1 (1 A g^-1) in a three-electrode system with 3 M KOH and 80 F g^-1 (1 A g^-1) in a symmetric two-electrode system with EMIMBF₄. The device exhibits an ultrahigh energy density of 81 W h kg^-1 at a power density of 1.3 kW kg^-1 and can still maintain at 60.8 W h kg^-1 when the power density is increased to 266.6 kW kg^-1. Moreover, the devices show superb stability that 94% of its initial capacitance is still maintained after 100 000 cycles at 20 A g^-1.

An FeP@C nanoarray vertically grown on graphene nanosheets: an ultrastable Li-ion battery anode with pseudocapacitance-boosted electrochemical kinetics

In order to develop promising anode materials for lithium-ion batteries (LIBs), a unique nanocomposite abbreviated as G⊥FP@C-NA, in which a carbon-coated FeP nanorod array (FP@C-NA) is vertically grown on a conductive reduced graphene oxide (G) network, has been successfully prepared via a scalable strategy. Benefiting from the distinctive structure, G⊥FP@C-NA exhibits much improved conductivity, structural stability and pseudocapacitance-boosted ultrafast electrochemical kinetics for Li storage. As a result, the G⊥FP@C-NA delivers a high Li-storage capacity (1106 mA h g-1 at 50 mA g-1), outstanding rate capability (565 mA h g-1 at 5000 mA g-1) and long-term cycling stability (1009 mA h g-1 at 500 mA g-1 after 500 cycles and 310 mA h g-1 at 2000 mA g-1 after 2000 cycles) when used as an anode material for LIBs. As expected, this kind of nanoarray structure is attractive and can also be extended to other electrode materials for various energy storage systems.