石油沥青包覆对石墨负极电化学性能的影响分析

本文立足于包覆改性天然石墨负极材料的作用和包覆改性最终效果的影响因素,简略阐述了石油沥青包覆石墨负极材料的研究背景,并从沥青软化点、包覆用量以及炭化温度几方面着手对石油沥青包覆对石墨负极电化学性能的影响机理进行了详细分析,旨在为相关研究人员提供参考,切实发挥出石油沥青包覆石墨负极材料的改性效果,在原有的基础上优化石墨负极电化学性能。

Effect of germanium on electrochemical performance of chain-like Co-P anode material for Ni/Co rechargeable batteries

Co-P （4.9% P） powders with a chain-like morphology were prepared by a novel chemical reduction method. The Co-P and germanium powders were mixed at various mass ratios to form Co-P composite electrodes. Charge and discharge test and electrochemical impedance spectroscopy （EIS） were carried out to investigate the electrochemical performance, which can be significantly improved by the addition of germanium. For instance, when the mass ratio of Co-P powders to germanium is 5：1, the sample electrode shows a reversible discharge capacity of 350.3 mA·h/g and a high capacity retention rate of 95.9% after 50 cycles. The results of cyclic voltammmetry （CV） show the reaction mechanism of Co/Co（OH）2 within Co-P composite electrodes and EIS indicates that this electrode shows a low charge-transfer resistance, facilitating the oxidation of Co to Co（OH）2.

Calculation model of edge carbon atoms in graphite particles for anode of lithium-ion batteries

Based on the hexagonal crystallite model of graphite,the electrochemical characteristics of carbon atoms on the edge and basal plane were proposed by analyzing graphite crystal structure and bonds of carbon atoms in different sites.A spherical close-packed model for graphite particle was developed.The fractions of surface carbon atoms（SCA） and edge carbon atoms（ECA） were derived in the expression of crystallographic parameters and particle size,and the effects of ECA on the initial irreversible capacity and the mechanisms of action were analyzed and verified.The results show that the atoms on the edge are more active for electrochemical reactions,such as electrolyte decomposition and tendency to form stable bond with other atoms and groups.For the practical graphite particle,corresponding modifying factors were introduced to revise the difference in calculating results.The revised expression is suitable for the calculation of the fractions of SCA and ECA for carbon materials such as graphite,disordered carbon and modified graphite.

Enhanced Photoelectrochemical Property of Zn Loaded TiO2 Nanotube Arrays Electrode

TiO2 nanotube arrays （TNTs） electrode loaded with Zn nanoparticles was prepared by anodization and the size of Zn nanoparticle loaded on TNTs electrode was controlled by chronoamperometry deposition time. Results of SEM and XRD analysis show that Zn nanoparticles had a diameter of about 15-25 nm when the deposition time was 3-5 s. The UV-Vis diffuse reflectance spectra show the Zn loaded harvest light with 480-780 nm more effectively than the unloaded sample. The photocurrent response of Zn loaded TNTs electrodes were studied, the results showed that TNTs electrodes loaded with Zn nanoparti-cles has 50% increased photocurrent response under high-pressure mercury lamp irradiation compared with unloaded TNTs electrode.

Carbonaceous mesophase spherule/activated carbon composite as anode materials for super lithium ion capacitors

A series of carbonaceous mesophase spherule/activated carbon composites were prepared as anode materials for super lithium ion capacitors using carbonaceous mesophase spherules as the core materials and pitch as the active carbon shell precursor.The structures of the composites were examined by scanning electron microscopy and X-ray diffractometry.The electrochemical performance was investigated in electric double layer capacitor and half-cell.The results show that,the composite exhibits good performance in both capacitor and battery with a high reversible capacity of 306.6 mA·h/g(0.2C) in the half-cell,along with a capacitance of 25.8 F/g in the capacitor when an optimum ratio of carbonaceous mesophase spherules to active carbon is adopted.The composite also shows a favorable rate performance and good cycle ability.A working model of this anode in super lithium ion capacitors was established.

MoSe_(2)@N, P-C composites for sodium ion battery

The conversion reaction-based anode materials of sodium ion batteries have relatively high capacity;however,the application of these materials is limited by their structural collapse due to the poor structure stability.In this work,MoSe_(2) nanosheets were synthesized by a solvothermal method.An organic solvent was intercalated into the MoSe_(2) materials to enlarge the interlayer spacing and improve the conductivity of the material.The MoSe_(2) material was coated with an organic pyrolysis carbon and then a uniform carbon layer was formed.The surface carbon hybridization of the nanosheet materials was realized by the introduction of heteroatoms during the sintering process.The as-prepared MoSe_(2)@N,P-C composites showed a superior rate performance as it could maintain the integrity of the morphology and structure under a high current density.The composites had a discharge specific capacity of 302.4 mA·h/g after 100 cycles at 0.5 A/g,and the capacity retention rate was 84.96%.

Influence of CsNO_3 as electrolyte additive on electrochemical property of lithium anode in rechargeable battery

Lithium metal is one of the most promising anode materials for rechargeable battery with high energy density,but its practical use is still hindered by two main problems,namely,lithium dendrite growth and low Coulombic efficiency.To address the issues,cesium nitrate(CsNO3)is selected as the additive to modify the electrolyte for lithium secondary battery.Here we report electrochemical performance of lithium secondary battery with different concentration of CsNO3 as electrolyte additive.The study result demonstrates that Coulombic efficiency of Li–Cu cells and the lifetime of symmetric lithium cells contained CsNO3 additive are improved greatly.Li–Cu cell with 0.05 mol/L CsNO3 and 0.15 mol/L LiNO3 as electrolyte additive presents the best electrochemical performance,having the highest Coulombic efficiency of around 97%and the lowest interfacial resistance.With increasing the concentration of CsNO3 as electrolyte additive,the electrochemical performance of cells becomes poor.Meanwhile,the morphology of lithium deposited films with CsNO3-modified electrolyte become smoother and more uniform compared with the basic electrolyte.

Preparation and effects of W-doping on electrochemical properties of spinel Li_4Ti_5O_(12) as anode material for lithium ion battery

W-doped Li4TisO12 in the form of Li4Ti4.95W0.osO12 was firstly synthesized via solid state reaction. X-ray diffraction （XRD） and scanning electron microscope （gEM） were employed to characterize the structure and morphology of Li4Ti4.psW0.05Ol2. W-doping does not change the phase composition and particle morphology, while remarkably improves its cycling stability at high charge/discharge rate. Li4Ti4.95W0.05O12 exhibits an excellent rate capability with a reversible capacity of 131.2 mA.h/g at 10C and even 118.6 mA.h/g at 20C. The substitution of W for Ti site can enhance the electronic conductivity of Li4TisO12 via the generation of mixing Ti4＋/Ti3＋, which indicates that Li4Ti4.psW0.05O12 is promising as a high rate anode for the lithium-ion batteries.

Preparation and electrochemical properties of Co_3O_4/graphite composites as anodes of lithium ion batteries

Co3O4/graphite composites were synthesized by precipitation of cobalt oxalate on the surface of graphite and pyrolysis of the precipitate, and the effects of graphite content and calcination temperature on the electrochemical properties of the composites were investigated. The samples were characterized by thermogravimetry and differential thermal analysis （TG/DTA）, X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS） and charge/discharge measurements. With increasing the graphite content, the reversible capacity of the Co3O4/graphite composites decreases, while cycling stability improves dramatically, and the addition of graphite obviously decreases the average potential of lithium intercalation/deintercalation. The reversible capacity of the composites with 50% graphite rises from 583 to 725 mA-h/g as the calcination temperature increases from 300 to 500 ℃, and the Co304/graphite composites synthesized at 400 ℃ show the best cycling stability without capacity loss in the initial 20 cycles. peaks, corresponding to the lithium intercalaction/deintercalation for The CV profile of the composite presents two couples of redox graphite and Co3O4, respectively. EIS studies indicate that the electrochemical impedance decreases with increasing the graphite content.

Hydrothermal Synthesis and Electrochemical Properties of Amorphous LiMoS2 as a High Capacity Anode Material for Lithium Ion Batteries

The LiMoS： anode material for lithium ion rechargeable batteries were synthesized by a hydrothermal method at 150 ℃. According to our measurements with X-ray diffraction, LiMoS2 was amorphous structure. Electrochemical measurements results showed that LiMoS2 exhibited large lithium storage capacities.

Oxygen-doped carbon host with enhanced bonding and electron attraction abilities for efficient and stable SnO_2/carbon composite battery anode

The coupling between electrochemically active material and conductive matrix is vitally important for high efficiency lithium ion batteries （LIBs）. By introducing oxygen groups into the nanoporous carbon framework, we accom- plish sustainably enhanced electrochemical performance for a SnO2/carbon LIB. 2-5 nm SnO2 nanoparticles are hydro- thermally grown in different nanoporous carbon frameworks, which are pristine, nitrogen- or oxygen-doped carbons. Compared with pristine and nitrogen-doped carbon hosts, the SnO2/oxygen-doped activated carbon （OAC） composite ex- hibits a higher discharge capacity of 1,122mAhg^-1 at 500 mA g^-1 after 320 cycles operation and a larger lithium storage capacity up to 680 mAhg-I at a high rate of 2,000 mA g^-1. The exceptional electrochemical performance originated from the oxygen groups, which could act as Lewis acid sites to attract electrons effectively from Sn during the charge process, thus accelerating reversible conversion of Sn to SnO2. Meanwhile, SnO2 nanoparticles are effectively bonded with carbon through such oxygen groups, thus preventing the electrochemical sintering and maintaining the cycling stability of the SnO2/OAC composite anode. The high electrochemical performance, low biomass cost, and facile preparation renders the SnO2/OAC composites a promising candidate for anode materials.

Waterproof lithium metal anode enabled by cross-linking encapsulation

Lithium (Li) metal is considered as the ultimate anode choice for developing next-generation high-energy batteries. However, the poor tolerance against moist air and the unstable solid electrolyte interphases (SEI) induced by the intrinsic high reactivity of lithium bring series of obstacles such as the rigorous operating condition, the poor electrochemical performance, and safety anxiety of the cell, which to a large extent hinder the commercial utilization of Li metal anode. Here, an effective encapsulation strategy was reported via a facile drop-casting and a following heat-assisted cross-linking process. Benefiting from the inherent hydrophobicity and the compact micro-structure of the cross-linked poly(vinylidene-co-hex afluoropropylene) (PVDF–HFP), the as-encapsulated Li metal exhibited prominent stability toward moisture, as well corroborated by the evaluations both under the humid air at 25 °C with 30% relative humidity (RH) and pure water. Moreover, the encapsulated Li metal anode exhibits a decent electrochemical performance without substantially increasing the cell polarization due to the uniform and unblocked ion channels, which originally comes from the superior affinity of the PVDF–HFP polymer toward nonaqueous electrolyte. This work demonstrates a novel and valid encapsulation strategy for humiditysensitive alkali metal electrodes, aiming to pave the way for the large-scale and low-cost deployment of the alkali metal-based high-energy-density batteries.

Nanotube-like hard carbon as high-performance anode material for sodium ion hybrid capacitors

Sodium ion hybrid capacitors（SIHCs） are of great concern in large-scale energy storage applications due to their good energy-and-power characteristic, as well as abundant reserves and low cost of sodium. However, the sluggish faradaic kinetics of anode materials severely limit the overall electrochemical performance of SIHC devices. Herein, we report an application of nanotube-like hard carbon（NTHC）anode material prepared by high-temperature carbonization（1150℃） of polyaniline（PANI） nanotubes for high-performance SIHCs. As a result, the assembled sodium ion half-cell with NTHC shows a high reversible capacity of 419.5 mA h g^-1at 0.05 A g^-1and a good rate performance of 74.6 mA h g^-1 at 2.5 A g^-1 in a potential window of 0-2 V（vs. Na/Na^＋）. On this basic, a SIHC using such NTHC as anode and a high-capacity activated carbon（APDC） as cathode is fabricated, which exhibits a high energy density of 133.0 W h kg^-1 at 2850 W kg^-1and still remains 100.9 W h kg^-1 at 14,250 W kg^-1. Within the potential range of 1.5-3.5 V, the SIHCs display an outstanding cycling stability tested at 2 A g^-1 with a good capacity retention of 82.5% even after 12,000 cycles.

Electrochemical Performance and ex situ Analysis of ZnMn2O4 Nanowires as Anode Materials for Lithium Rechargeable Batteries

One-dimensional ZnMn2O4 nanowires have been prepared and investigated as anode materials in Li rechargeable batteries. The highly crystalline ZnMn2O4 nanowires about 15 nm in width and 500 nm in length showed a high specific capacity of about 650 mAh.g-1 at a current rate of 100 mA.g-1 after 40 cycles. They also exhibited high power capability at elevated current rates, i.e., 450 and 350 mAh.g 1 at current rates of 500 and 1000 mA.g 1, respectively. Formation of Mn3O4 and ZnO phases was identified by ex situ X-ray diffraction （XRD） and transmission electron microscopy （TEM） studies after the initial discharge-charge cycle, which indicates that the ZnMn2O4 phase was converted to a nanocomposite of Mn3O4 and ZnO phases immediately after the electrochemical conversion reaction.

A unique co-recovery strategy of cathode and anode from spent LiFePO_(4) battery

Along with the explosive growth in the market of new energy electric vehicles,the demand for Li-ion batteries(LIBs)has correspondingly expanded.Given the limited life of LIBs,numbers of spent LIBs are bound to be produced.Because of the severe threats and challenges of spent LIBs to the environment,resources,and global sustainable development,the recycling and reuse of spent LIBs have become urgent.Herein,we propose a novel green and efficient direct recycling method,which realizes the concurrent reuse of LiFePO_(4)(LFP)cathode and graphite anode from spent LFP batteries.By optimizing the proportion of LFP and graphite,a hybrid LFP/graphite(LFPG)cathode was designed for a new type of dualion battery(DIB)that can achieve co-participation in the storage of both anions and cations.The hybrid LFPG cathode combines the excellent stability of LFP and the high conductivity of graphite to exhibit an extraordinary electrochemical performance.The best compound,i.e.,LFP:graphite=3:1,with the highest reversible capacity(~130 mAhg^(-1) at 25 mAg^(-1)),high voltage platform of 4.95 V,and outstanding cycle performance,was achieved.The specific diffusion behavior of Li^(+) and PF_(6)^(-) in the hybrid cathode was studied using electrode kinetic tests,further clarifying the working mechanism of DIBs.This study provides a new strategy toward the large-scale recycling of positive and negative electrodes of spent LIBs and establishes a precedent for designing new hybrid cathode materials for DIBs with superior performance using spent LIBs.