High Performance Negative Electrode Material Research Articles

Exploring the potential of di-boron di-nitride monolayer (o-B2N2) as a K-ion battery anode: A DFT study

Due to favorable future use of electrochemical energy storage systems in portable electronic devices, these systems have received much attention. Employing these systems in "smart" clothes equipped with piezoelectric pieces to gain energy from body movement and roll-up displays is promising. Nevertheless, further development of these technologies is a significant challenge due to lack of appropriate battery electrodes that supply desirable electrochemical performance. 2D flexible and light materials with remarkable chemical and physical attributes such as acceptable conductivity, high surface metal diffusivity, hydrophilic surfaces, and mechanical strengths were introduced as potential options for battery electrodes. In present research, 2D orthorhombic di-boron di-nitride monolayer (o-B2N2) as a novel 2D boron nitride allotrope has been investigated. Systematically, various impacting factors like their electrochemical and electronic features (theoretical capacity, equilibrium voltage, binding strength, etc.) were investigated. It is noteworthy that specific capacity of K-ion batteries (KIBs) reaches 2347 mAh.g-1. In addition, the existence of o-B2N2 ring accelerates the diffusion of K-ions, and diffusion barriers are 0.14 eV. Mean open circuit voltage (OCV) and low diffusion barrier of o-B2N2 monolayer guarantee long service life and fast charging/discharging for practical purposes. Based on results, monolayer o-B2N2 is proper as a high-performance negative electrode material in KIBs.

Synthesis and modification of corncob-based carbon as high performance negative material for supercapacitor

Porous carbons derived from agricultural waste biomass are ideal active materials for eco-friendly and low-cost supercapacitors electrode materials. However, the challenge remains to further functional modification of biomass-based carbon to achieve high specific capacitance. Herein, PPD-modified porous carbon (MPC) was synthesized by KOH soaking coupled with facile carbonization method of natural corncob and covalently graft of p-phenylenediamine. The MPC exhibits a high specific capacitance of 393 F·g-1 at a scan rate of 5mV·s-1 in a three electrode system in a 1 M KOH aqueous electrolyte solution. MPC was expected to become promising active materials for high performance negative electrode materials.

Binder-Free Zinc-Iron Oxide as a High-Performance Negative Electrode Material for Pseudocapacitors.

The interaction between cathode and anode materials is critical for developing a high-performance asymmetric supercapacitor (SC). Significant advances have been made for cathode materials, while the anode is comparatively less explored for SC applications. Herein, we proposed a high-performance binder-free anode material composed of two-dimensional ZnFe2O4 nanoflakes supported on carbon cloth (ZFO-NF@CC). The electrochemical performance of ZFO-NF@CC as an anode material for supercapacitor application was examined in a KOH solution via a three-electrode configuration. The ZFO-NF@CC electrode demonstrated a specific capacitance of 509 F g−1 at 1.5 A g−1 and was retained 94.2% after 10,000 GCD cycles. The ZFO-NF@CC electrode showed exceptional charge storage properties by attaining high pseudocapacitive-type storage. Furthermore, an asymmetric SC device was fabricated using ZFO-NF@CC as an anode and activated carbon on CC (AC@CC) as a cathode with a KOH-based aqueous electrolyte (ZFO-NF@CC||AC@CC). The ZFO-NF@CC||AC@CC yielded a high specific capacitance of 122.2 F g−1 at a current density of 2 A g−1, a high energy density of 55.044 Wh kg−1 at a power density of 1801.44 W kg−1, with a remarkable retention rate of 96.5% even after 4000 cycles was attained. Thus, our results showed that the enhanced electrochemical performance of ZFO-NF@CC used as an anode in high-performance SC applications can open new research directions for replacing carbon-based anode materials.

In situ form core-shell carbon nanotube-imide COF composite for high performance negative electrode of pseudocapacitor

High performance negative electrode material of pseudocapacitor is of paramount importance for the device energy storage capacity. Herein, a novel carbon nanotube-imide COF composite negative electrode material was successfully prepared by in situ growth of imide COF on the wall of nanotubes containing amine groups. FT-IR, XRD, SEM and HR-TEM verify that the core-shell composite was formed. Driven by the π-π interaction between carbon nanotube and imide COF, the composite exhibits high electron conductivity. N2 adsorption-desorption test further displays that the composite still possesses adequate porous structure with a high specific surface area of 386 m2 g−1. The unique core-shell structure enables the carbon nanotube-imide COF composite with high energy storage capacity, a high specific capacitance of 278 F g−1 at 0.5 A g−1 between -1 V to 0 V in the neutral electrolyte, among the best results for the recent reported high performance negative pseudocapacitance organic materials. Interestingly, the composite still gives a high specific capacitance of 72 F g−1 at high current density of 50 A g−1. These interesting energy storage properties should be attributed to the synergetic mechanism between carbon nanotube and COF. Moreover, the asymmetric device assumed with the carbon nanotube-imide COF composite as the negative material and the RuO2 as the positive material, displays high energy density of 25.9 W h kg−1 with a power density of 357.2 W kg−1. The composite negative material design idea would offer reference for other high performance energy storage materials.

Interfacial Engineering and a Low-Crystalline Strategy for High-Performance Supercapacitor Negative Electrodes: Fe2P2O7 Nanoplates Anchored on N/P Co-doped Graphene Nanotubes.

Developing novel hybrid negative electrode materials with high specific capacity, rate capacitance, and long-term cycle stability is a key factor for pushing large-scale application of supercapacitors. However, construction of robust interfaces and low-crystalline active materials plays a crucial role in realizing the target. In this paper, a one-step phosphorization approach was employed to make low-crystalline Fe2P2O7 nanoplates closely bonded to N/P-co-doped graphene nanotubes (N/P-GNTs@b-Fe2P2O7) through interfacial chemical bonding. The N and P heteroatoms as substitutions for C in GNT skeletons can introduce rich electronic centers, which induces Fe2P2O7 to fix the surface of N/P-GNTs through Fe-N and Fe-P bonds as confirmed by the characterizations. Moreover, the low-crystalline active materials own a disordered internal structure and numerous defects, which not only endows with excellent conductivity but also provides many active sites for redox reactions. Benefiting from the synergistic effects, the prepared N/P-GNTs@b-Fe2P2O7 can not only deliver a high capacity of 257 mA h g-1 (927 F g-1) at 1 A g-1 but also present an excellent rate capability of 184 mA h g-1 (665 F g-1) at 50 A g-1 and outstanding cycle stability (∼90.6% capacity retention over 40,000 cycles). Furthermore, an asymmetric supercapacitor was assembled using the obtained N/P-GNTs@b-Fe2P2O7 as electrode materials, which can present the energy density as high as 83.3 W h kg-1 at 791 W kg-1 and long-term durability. Therefore, this strategy not only offers an effective pathway for achieving high-performance negative electrode materials but also lays a foundation for further industrialization.

Natural biomass-derived porous carbons from buckwheat hulls used as anode for lithium-ion batteries

Biomass-derived porous carbon has provided new ideas for the preparation of new energy materials due to its cost-effectiveness and abundance, promoting its application in lithium-ion batteries. In this paper, porous carbon was prepared by a simple and economical carbonization process with buckwheat hulls as raw material and CaCl2 as an activator to improve the electrochemical performance of carbon materials. When the mass ratio of buckwheat hull and CaCl2 is 1:2.5, the porous carbon materials with a specific surface area of 351.018 m2 g−1 has a specific capacity of 715.0 mAh g−1 (about 1.9 times the specific capacity of the graphite anode) after 150 cycles at 0.2C and 444.8 mAh g−1 after 500 cycles at 5C. These results confirm that the porous structure of porous carbon materials contributes to the rapid transport of lithium ions in the electrolyte and electrode material. In addition, this study shows that the use of waste biomass, i.e., buckwheat hulls, overcomes the deficiency of low capacity of graphite anode and provides a new option for the preparation of high-performance negative electrode material for LIBs.

Engineering the performance of negative electrode for supercapacitor by polyaniline coated Fe3O4 nanoparticles enables high stability up to 25,000 cycles

Supercapacitors (SCs) have proven remarkable interest in portable digital devices because of their long life span and high power densities. However, low energy densities of SCs hindered their applications due to the lack of high-performance negative electrode materials. In this work, we demonstrated the successful surface engineering of iron oxide nanoparticles (Fe3O4-NPs) by polyaniline (PANI) coating through a facile low-temperature hydrothermal method. The polyaniline coated iron oxide nanoparticles (Fe3O4/PANI-NPs) were characterized by a series of techniques including XRD, FT-IR, RAMAN, XPS, TGA, BET, SEM, and TEM. Fe3O4-NPs and Fe3O4/PANI-NPs are investigated as negative electrode materials for SCs in basic potassium hydroxide (KOH) electrolyte. The Fe3O4/PANI-NPs sample possesses specific capacitance of 1669.18 F g−1 while Fe3O4-NPs exhibits 1351.13 F g−1 at 1 A g−1 at identical conditions. The Fe3O4/PANI-NPs sample exhibits remarkable electrochemical cycling performance (96.5%) over pristine Fe3O4-NPs (92%) at high current density of 15 A g−1 by exceeding the 25,000 times charge/discharge cycles. The PANI coating not only offers a strong shell to avoid degradation of the material but also contributes to enhancing the capacitance with outstanding stability. Furthermore, we analyzed the charge storage contributions by implementing the power's law and interestingly Fe3O4/PANI-NPs sample exhibits high capacitive type storage (85% capacitive at 10 mVs−1). Based on our experiments, Fe3O4/PANI-NPs shows exceptional high electrochemical results in basic electrolyte with excellent stability and surpass most of recently reported work based on the iron oxides and their composites. Therefore, the proposed strategy can be applied to fabricate the high-performance negative electrode materials for supercapacitors.

RETRACTED: Ultra-fast one-step synthesis and surface engineering of mesoporous 3D α- Fe2O3 hollow nanospheres for high-performance and stable negative electrode for supercapacitors

Abstract Supercapacitors (SCs) have received considerable attention in portable digital devices because of their long life span and high power densities. However, low energy densities of SCs limited their practical applications due to the lack of high-performance negative electrode materials. This work demonstrates the surface engineering of α-Fe2O3 hollow nanospheres (α-Fe2O3-HNS) by controlled crystal growth through hollowing mechanism by the Ostwald ripening approach using facile one-step and low-cost hydrothermal method. The formation of α-Fe2O3-HNS was confirmed by scanning and transmission electron microscopy and further characterized by a variety of analytical methods. To investigate the electrochemical properties of α-Fe2O3-HNS, we systemically tested it in aqueous electrolyte under the extended potential window of −1.2–0.0 V versus Ag/AgCl. Among three samples of α-Fe2O3 nanospheres, the α-Fe2O3-HNS sample manifests a record high specific capacitance of 1041.18 F g−1 while partially hollow and solid α-Fe2O3 nanospheres displayed relatively low specific capacitances of 534.31 and 325.38 F g−1 at 1 A g−1, respectively. The α-Fe2O3-HNS sample demonstrates excellent cycling retention of 98.88% while other samples retained 94.23% and 88.25%, respectively after 10,000 cycles at a high current density of 15 A g−1. The surface engineering of α-Fe2O3-HNS offers not only the high surface area but also allows a large number of electroactive sites at electrode/electrolyte contact. Furthermore, we investigated the quantification of capacitive and diffusion controlled stored charge for high performance charge storage kinetics of as-prepared electrodes, by employing power’s law and impressively α-Fe2O3-HNS sample reveals high capacitive type charge storage of (85% at 10 mV/s). The obtainable results fully exhibit the unique advantage of a hollow structure to fabricate superior negative electrode materials for supercapacitors.

In situ polymerized Ti3C2Tx/PDA electrode with superior areal capacitance for supercapacitors

To solve the restacking of the Ti3C2Tx nanosheets and destroy of electrode microstructure during cycles and gain high-performance electrode for supercapacitors, Ti3C2Tx/PDA composite film electrode was rationally designed and successfully synthesized by one-step in situ polymerization of dopamine on the surface of the Ti3C2Tx nanosheets. The as-synthesized Ti3C2Tx/PDA composite electrode achieved a superior areal capacitance of 715 mF/cm2 at a scan rate of 2 mV/s and maintained 95.5% of initial capacitance after 10000 cycles, exhibiting long-term cycling stability. The areal capacitance can be enhanced to 3440 mF/cm2 when the mass loading increases to 13.6 mg/cm2. The improved electrochemical performance and outstanding electrochemical stability can be attributed to the effective suppressing the restacking of Ti3C2Tx sheets and increasing interlayer spacing by introducing PDA, which could be beneficial to expose more surface active sites, shorten the diffusion path of electrolyte ions, promote electron transport and fast Faradaic reaction. Our work opens new design space to develop the high performance negative electrode materials.

Three-Dimensional Cobalt Phosphide Nanowire Arrays as Negative Electrode Material for Flexible Solid-State Asymmetric Supercapacitors.

Despite the great progress that has been accomplished in supercapacitors, the imbalance of the development of positive and negative electrode materials still remains a critical issue to achieve high energy density; therefore, exploring high-performance negative electrode materials is highly desirable. In this article, three-dimensional cobalt phosphide (CoP) nanowire arrays were synthesized on a carbon cloth and were utilized as a binder-free supercapacitor negative electrode. The as-synthesized CoP nanowire arrays presented a high capacitance of 571.3 mF/cm2 at a current density of 1 mA/cm2. By using CoP nanowire arrays as the negative electrode and MnO2 nanowire arrays as the positive electrode, a flexible solid-state asymmetric supercapacitor has been fabricated and has exhibited excellent electrochemical performance, such as a high energy density of 0.69 mWh/cm3 and a high power density of 114.2 mW/cm3. In addition, the solid-state asymmetric supercapacitor shows high cycle stability with 82% capacitance retention after 5000 charge/discharge cycles. This work demonstrates that CoP is a promising negative electrode material for high-performance supercapacitor applications.

Hybrid graphene@MoS2@TiO2 microspheres for use as a high performance negative electrode material for lithium ion batteries

MoS2 nanosheets were impregnated into mesoporous TiO2 and encapsulated by a graphene layer resulting in excellent Li ion storage properties.

Synthesis of nanostructured Ni3S2 with different morphologies as negative electrode materials for lithium ion batteries

Ni3S2 with different morphologies (nanoflakes, nanosheets, nanoparticles) have been synthesized by simply altering the sulphur sources (thioacetamide, thiourea and sodium thiosulfate) of a hydrothermal process. The obtained three carbon-free nanostructures are evaluated as negative electrode materials for lithium ion batteries. Ni3S2 nanoflakes exhibit the best cycle and rate performance among the samples prepared, which is benefited from their small particle size and porous structure. It maintains a reversible capacity of 861 mA h g−1 after 70 cycles at a current density of 0.4 A g−1, and a reversible capacity of 514 mA h g−1 even at a current density as high as 4.0 A g−1. These features make Ni3S2 nanoflakes a promising candidate as high performance negative electrode material for lithium ion batteries.

Amorphous monodispersed hard carbon micro-spherules derived from biomass as a high performance negative electrode material for sodium-ion batteries

This paper reports monodispersed hard carbon micro-spherules with a high energy density, high initial coulombic efficiency and excellent cycle performance.

TiO2(B)/Anatase Composites Synthesized by Spray Drying as High Performance Negative Electrode Material in Li‐Ion Batteries

The power of spray-dried TiO2 in LIBs: TiO2(B)/anatase is synthesized by spray drying and investigated as negative electrode material in Li-ion batteries. It exhibits excellent Li-ion storage performances, especially at high charge/discharge rates. The presence of the β phase of TiO2 improves Li-ion diffusivity. Additionally, the scalable synthesis method also allows for Nb-doping, which assists in the maintenance of the electronic conductivity as the thickness of film increases.

Layered titanate nanostructures and their derivatives as negative electrode materials for lithium-ion batteries

Ti-based materials have been intensively investigated and considered as good potential negative electrode materials for lithium-ion batteries (LIBs) due to their high safety, superior rate capability and excellent cyclic stability. This feature article summarizes the recent progress of a new class of layered titanate (H2TinO2n+1·H2O) nanostructures and their derivatives, including TiO2 polymorphs, novel titanate nanostructures of Zn2Ti3O8, Li2MTi3O8 (M = Co, Zn, Mg) and Li4Ti5O12, as high performance negative electrode materials for LIBs. The effects of the composition, crystal structure and morphology on lithium-ion intercalation properties are highlighted and analyzed.

Entangled Germanium Nanowires and Graphite Nanofibers for the Anode of Lithium-Ion Batteries

High performance negative electrode materials for lithium-ion batteries were fabricated using germanium nanowire (GeNW) and graphite nanofiber (GNF) composites prepared by a low-pressure chemical vapor deposition (CVD) method. The promising high power rate anode material GeNWs were grown on the surface of a GNF bundle to mutually form the entangled structure. The high contact area between the GeNWs and GNFs enabled electrons to be efficiently transported and the GeNWs entwined with GNFs minimized the degradation of the electrochemical characteristics. These composite materials for the anode of lithium-ion batteries showed a very constant high specific capacity of ∼1,200 mAh g−1 with little decline of the cycling performance while the rate capability was significantly improved.