Electrochemical performance of surfactant-processed LiFePO4 as a cathode material for lithium-ion rechargeable batteries

This study focuses on the effect of addition of surfactant as a dispersing agent during vibratory ball milling of LiFePO₄ (LFP) precursor materials on the electrochemical performance of solid-state reaction synthesized LFP for lithium-ion battery cathode material. LFP particles formed after calcinations of ball milled LFP precursors (Li₂CO₃, FeC₂O₄, and NH₄H₂PO₄) showed better size uniformity, morphology control, and reduced particle size when anionic surfactant (Avanel S-150) was used. The specific surface area of LFP particles increased by approximately twofold on addition of surfactant during milling. These particles showed significantly enhanced cyclic performance during charge/discharge due to a reduced polarization of electrode material. Electrodes fabricated from LFP particles by conventional milling process showed a 22 % decrease in capacity after 50 cycles, whereas the performance of electrode prepared by surfactant processed LFP showed only 3 % loss in capacity. The LFP particles were characterized using XRD, FE-SEM, particle size distribution, density measurement, and BET-specific surface area measurement. Electrochemical impedance spectra and galvanostatic charge/discharge test were performed for the electrochemical performance using coin-type cell.     

Sulphide based anode material for lithium rechargeable battery

In this study, lead sulphide (PbS) was prepared by the chemical bath deposition technique. The sample was characterized by X-ray diffraction (XRD), Energy Dispersive Analysis of X-rays (EDAX) and cyclic voltammetry. EDAX spectrum shows peaks attributable to lead and sulphur. The EDAX analysis also shows that the prepared sample is stoichiometric. Cyclic voltammetry experiments were recorded at 100 mV·s⁻¹ and 400 mV·s⁻¹ scan rates. Results show that the rate controlling electrochemical reaction is electron transfer. The presence of redox waves shows that the lithium intercalation and deintercalation can occur as a result of lattice expansion in PbS. There were no differences in the PbS XRD data before and after the cyclic voltammetry experiments indicating that the PbS structure is not modified upon lithium ion intercalation and deintercalation in PbS. The discharge characteristics for 35 cycles of the cell using the LiCoO₂/PbS couple is presented indicating the possible development of such materials as anode in lithium ion cells.     

基于BC3NT的混合系锂空气电池正极第一性原理研究

文章采用第一性原理,利用掺杂硼的碳纳米管(BC₃NT)容易产生拓扑缺陷的特点,将其用作混合系锂空气电池正极材料,研究了BC₃NT拓扑缺陷电子性质及氧分子吸附.结果表明:BC₃NT产生的拓扑缺陷使得氧气在纳米管外表面吸附更加稳定,且缺陷环越大,吸附越稳定.七元环缺陷、八元环缺陷分别会使氧气在纳米管外表面发生半解离吸附和完全解离吸附,有利于氧还原反应的发生;通过布居分析电荷转移进一步验证了缺陷环越大,转移电荷越多,吸附越稳定. BC₃NT能增强对氧分子的解离吸附能力,有利于氧还原反应的进行.该材料适合用作混合系锂空气电池正极,有利于提高其性能.     

Electrochemical cell performance studies on all-solid-state battery using nano-composite polymer electrolyte membrane

All-solid-state proton-conducting polymeric batteries have been fabricated in the cell configurations: Zn + ZnSO₄·7H₂O (anode) || polyethylene oxide (PEO):NH₄HSO₄ + SiO₂ || MnO₂ + C (cathode) and Zn + ZnSO₄·7H₂O (anode) || PEO:NH₄HSO₄ + SiO₂ || PbO₂ + V₂O₅ + C (cathode). Nano-composite proton-conducting polymeric membrane in wt.% composition, 92PEO: 8 NH₄HSO₄ + 3 SiO₂, synthesized by solution cast technique, has been used as electrolyte. Dispersal of nanosized (8 nm) fumed-SiO₂ particles resulted into an enhancement in the room temperature conductivity of polymer electrolyte host, 92PEO: 8 NH₄HSO₄ (wt.%), approximately by an order of magnitude with the substantial increase in the mechanical strength of the films. Details on the electrolyte film casting and ion transport characterization studies have been discussed elsewhere in the literature. However, a brief mention has been made for reference. An open circuit voltage in the range 1.5–1.8 V, obtained for both the batteries, is in very good agreement with the value reported. The cell performance has been studied under varying load conditions. Paper presented at the Third International Conference on Ionic Devices (ICID 2006), Chennai, Tamilnadu, India, Dec. 7–9, 2006.     

Electrochemical performance of La2O3-coated layered LiNiO2 cathode materials for rechargeable lithium-ion batteries

Uncoated and La₂O₃-coated LiNiO₂ cathode materials were synthesized by polymeric sol gel process using metal nitrate precursors at 600 °C for 10 h. The structure and electrochemical properties of the surface-coated LiNiO₂ materials were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry, charge/discharge and electrochemical impedance spectroscopy techniques. X-ray powder diffraction and SEM result show that no significant bulk structural differences were observed between the lanthanum oxide coated and pristine LiMn₂O₄. The galvanostatic charge/discharge studies on the uncoated and lanthanum oxide-coated LiNiO₂-positive material at 0.5-C rate in the potential range between 3 and 4.5 V revealed that lanthanum oxide-coated positive electrode material has enhanced charge/discharge capacities; 2.0 wt.% of lanthanum oxide-coated LiNiO₂-positive material has satisfied the structural stability, high reversible capacity and high electrochemical performances.     

Electrochemical performance of lead acid battery using ammonium hydrogen sulphate with different alkyl groups

In this work, the application of ionic liquids (ILs)??mono-, bicycyclohexyl, monohexyl and tetrahexyl ammonium hydrogen sulphate??as electrolyte additives on the electrochemical performance of lead acid batteries is proposed. The electrochemical behaviour of Pb?C1.66% Sb?C0.24% Sn alloy in sulphuric acid solution is investigated in the presence of the mentioned ILs with different numbers of alkyl or cycloalkyl chains. Particularly, the hydrogen and oxygen evolution potential and anodic layer characteristics were studied using cyclic and linear sweep voltammetric methods. The obtained results indicate that hydrogen evolution overpotential of Pb/Sb/Sn alloy in the presence of ILs increases. This overpotential mainly depends on the concentration of ILs and the number of alkyl and cycloalkyl chains on the cations. Also, the difference between the oxygen oxidation potential in anodic and cathodic scans (?E) decreases using different ILs.     

Electrochemical behavior of hydrated molybdenum oxides in rechargeable lithium batteries

Oxide-hydrates of molybdenum (OHM) are investigated as 3-volt cathode materials for rechargeable lithium batteries. These materials with different water content showed a much better performance than that of MoO₃ as cathode of the rechargeable lithium battery. We report the electrochemical characteristics of Li//OHM batteries using the oxides and oxide-hydrates of molybdenum which were synthesized from molybdic acid. The oxide has a corrugated layered structure consisting of corner-shared MoO₆ octahedra. This structure provides electronic conductivity within basal layer and high lithium ion mobility between layers. The mechanism of dehydration and structural rearrangement of molybdic acid during heat treatment were studied by thermal analysis, x-ray diffraction, and Raman spectroscopy. Thermal analysis indicates a two-step dehydration and formation of orthorhombic α-MoO₃ and monoclinic ß-MoO₃. Discharge profiles and kinetics are dependent on the amount of “structural water” into the host lattice. The electroinsertion of Li ions occurs mainly in two steps in the potential range between 3.0 and 1.5 V (compositional range 0.0≤x(Li)≤1.5).     

Synthesis and characterization of Co-doped lithium manganese oxide as a cathode material for rechargeable Li-ion battery

An attempt has been made to prepare cobalt-doped lithium manganese oxide with three different concentrations by simple molten salt method to enhance the electrical property of Li₄Mn₅O₁₂. Prepared samples were examined by XRD and SEM to identify its structure and morphology. Electrical properties were identified by impedance and conductivity analysis, and it was found that the material exhibits negative temperature coefficient (NTCR) property, i.e., semi-conducting nature. Among the various concentrations, 0.5 mol of Co-doped lithium manganese oxide has shown good conductivity of 3.1 × 10^?5 S cm^?1 at 433 K.     

A ZnO/PVA/PAADDA composite electrode for rechargeable zinc-air battery

Ionics - A ZnO/PVA/PAADDA composite electrode for rechargeable zinc-air battery was prepared by chemical cross-linked PVA (polyvinyl alcohol) with poly(acrylamide-co-diallyldimethylammonium...     

Performance studies on composite gel polymer electrolytes for rechargeable magnesium battery application

Effect of micron-sized MgO particles dispersion on poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF–HFP) based magnesium-ion (Mg²⁺) conducting gel polymer electrolyte has been studied using various electrical and electrochemical techniques. The composite gel films are free-standing and flexible with enough mechanical strength. The optimized composition with 10 wt% MgO particles offers a maximum electrical conductivity of ∼6×10⁻³ S cm⁻¹ at room temperature (∼25°C). The Mg²⁺ ion conduction in gel film is confirmed from cyclic voltammetry, impedance spectroscopy and transport number measurements. The applicability of the composite gel electrolyte to a rechargeable battery system has been examined by fabricating a prototype cell consisting of Mg (or Mg–MWCNT composite) and V₂O₅ as negative and positive electrodes, respectively. The rechargeability of the cell has been improved, when Mg metal was substituted by Mg–MWCNT composite as negative electrode.     

Advanced characterization and calculation methods for rechargeable battery materials in multiple scales

The structure-activity relationship of functional materials is an everlasting and desirable research question for material science researchers,where characterization and calculation tools are the keys to deciphering this intricate relationship.Here,we choose rechargeable battery materials as an example and introduce the most representative advanced characterization and calculation methods in four different scales:real space,energy,momentum space,and time.Current research methods to study battery material structure,energy level transition,dispersion relations of phonons and electrons,and time-resolved evolution are reviewed.From different views,various expression forms of structure and electronic structure are presented to understand the reaction processes and electrochemical mechanisms comprehensively in battery systems.According to the summary of the present battery research,the challenges and perspectives of advanced characterization and calculation techniques for the field of rechargeable batteries are further discussed.     

Electrochemical characteristics of ZrSe2 in a secondary lithium battery

Electrochemical characteristics of the transition metal dichalcogenide ZrSe₂ were investigated as a cathode material. Lithium intercalated ZrSe₂ showed a high reversibility of lithium ions in the non-aqueous solution. The discharge/ charge cycle was performed up to 160 times without deterioration.     

Electrochemical characteristics of transition-metal trichalcogenides in the secondary lithium battery

Transition-metal trichalcogenides have been investigated as cathode materials in the lithium electrochemical cell. Three lithium ions per TiS₃ molecule have been found to be marginally reversible, while only one lithium is reversible in TaSe₃. This difference may be related to exfoliation of these substances due to the progress of lithium intercalation.     

Bifunctional oxygen electrocatalysts for rechargeable zinc−air battery based on MXene and beyond

Oxygen electrocatalysts are of great importance for the air electrode in zinc–air batteries (ZABs). Owing to large surface area, high electrical conductivity and ease of modification, two-dimensional (2D) materials have been widely studied as oxygen electrocatalysts for the rechargable ZABs. The elaborately modified 2D materials-based electrocatalysts, usually exhibit excellent performance toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which have attracted extensive interests of worldwide researchers. Given the rapid development of bifunctional electrocatalysts toward ORR and OER, the latest progress of non-noble electrocatalysts based on layered double hydroxides (LDHs), graphene, and MXenes are intensively reviewed. The discussion ranges from fundamental structure, synthesis, electrocatalytic performance of these catalysts, as well as their applications in the rechargeable ZABs. Finally, the challenges and outlook are provided for further advancing the commercialization of rechargeable ZABs.     

Cellulose-derived carbons as a high performance anodic material for Na-ion battery

A facile and easily scalable method for producing disordered carbons as active materials for sodium ion (Na-ion) battery anode has been developed. The materials were synthesized by two-step pyrolysis of microcrystalline cellulose at the final temperature in the range of 950 to 1250 °C, followed by pyrolytic carbon (PC) coating. The effect of heat-treatment temperature (HTT) and PC process on heteroatom content (elemental analysis), porous texture (N₂ and CO₂ adsorption), and electrochemical performance (coin-type half-cell) was analyzed. Increasing HTT results in remarkable decrease of oxygen content, from 4.4 to 1.4 wt.%, and the surface area accessible for N₂ molecules (microporosity), from 502 to 114 m² g^?1, while the carbonization degree, expressed as the H/C atomic ratio and the area probed by CO₂ (ultramicropores) are only slightly reduced. Elevating carbonization temperature gradually decreases the irreversible C_irr and increases the reversible C_rev capacities in the first charge/discharge cycle. PC coating, applied to 1000 °C, seems to be less effective in improving electrochemical properties than HTT factor despite strong reduction of porosity and surface chemistry. Simple heat treatment at 1200 °C seems to be optimal to produce anodic material with the best electrochemical performance in a wide range of current load: coulombic efficiency of 0.78 and C_rev of 306 or 261 mAh g^?1 at 20 or 500 mA g^?1, respectively.     

Solution synthesis of boron substituted LiMn2O4 spinel oxide for use in lithium rechargeable battery

An attempt has been made to synthesize LiMn₂O₄ spinel and boron substituted LiMn₂O₄ with atomic concentration of boron ranging from 0.01–0.20 and using glutaric acid as a chelating agent. The spinels have been characterized using PXRD, CV and galvanostatic charge-discharge studies. The precursor obtained from the glutaric acid assisted gel was calcined initially at 300 °C for 4 h to obtain the compound and finally at 800 °C for 4 h so as to obtain homogeneity, high degree of purity and crystallinity for better electrochemical performance. This paper suggests that glutaric acid assisted B³⁺ doped (LiB_xMn_2−xO₄) spinel was found to be as an apt candidate with good electrochemical performance for use in lithium battery.     

Study on ionic conductivity of polymer electrolyte plasticized with PEG–aluminate ester for rechargeable lithium ion battery

We have synthesized poly(ethylene glycol) (PEG)-aluminate ester as a plasticizer for solid polymer electrolytes. The thermal stability, ionic conductivity and electrochemical stability of the polymer electrolyte which consist of poly(ethylene oxide) (PEO)-based copolymer, PEG–aluminate ester and lithium bis-trifluoromethanesulfonimide (LiTFSI) were investigated. Addition of PEG–aluminate ester increased the ionic conductivity of the polymer electrolyte, showing greater than 10^− 4 S cm^− 1 at 30 °C. The polymer electrolyte containing PEG–aluminate ester retained thermal stability of the non-additive polymer electrolyte and exhibited electrochemical stability up to 4.5 V vs. Li⁺/Li at 30 °C.     

包含液相扩散方程简化的锂离子电池电化学模型

锂离子电池的电化学模型对于电池特性分析和电池管理具有重要意义,但是准二维(P2D)模型复杂度太高,为了在保证模型精度的基础上尽量降低复杂度,本文提出了一种包含液相简化的P2D (LSP2D)模型,该模型首先基于电化学平均动力学将电池端电压化简成为仅耦合固相Li+浓度c_s和液相Li+浓度c_e的方程,然后进一步对表达c_s和c_e演化规律的偏微分方程进行抛物线近似化简,使得最终的模型由多项式组成.COMSOL仿真表明在放电倍率为1C时该模型与单粒子(SP)模型的估算精度和速度相当,但在放电倍率为3C时,该模型的估算时间比P2D模型减少了99.73%,与SP模型相当,估算精度相比SP模型有大幅度提升.