New Ni0.5Ti2 (PO4)3@C NASICON-type electrode material with high rate capability performance for lithium-ion batteries: Synthesis and electrochemical properties

Ni0.5Ti2(PO4)3/C NASICON‐type phosphate is introduced as a new anode material for lithium‐ion batteries (LIBs). Ni0.5Ti2(PO4)3/C was synthesized through the sol–gel route and delivered some remarkable electrochemical performances. Specifically, the Ni0.5Ti2(PO4)3/C electrode demonstrates a high rate capability performance and delivers high reversible capacities ranging from 130 mAh g−1 to about 111 mAh g−1 at current rates ranging from 0.1 C to 5 C in the voltage window of 1.85–3 V (vs. Li+/Li). In the same voltage range, the material reaches an initial capacity of 105 mAh g−1 with a capacity retention of about 82 % after 1000 cycles at the high current rate of 10  C. The electrodes are also tested in the wider voltage range of 0.5–3 V (vs. Li+/Li) and show good reversibility and rate capability performance. Moreover, the Ni0.5Ti2(PO4)3/C electrodes enable fast Li+ diffusion (in the order of 10−13 cm2 s−1) compared with other NASICON‐type materials. As a result, a first discharge capacity of 480 mAh g−1 is reached

Les materiaux d'electrodes positives A_xNi_1_-_yCo_yO_2 (A=Li, Na). Etude des relations: structure, proprietes physiques et comportement electrochimique

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 83859 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Effect of thermal treatment used in the sol-gel synthesis of Li4Ti5O12 spinel on its electrochemical properties as anode for lithium ion batteries

The effect of the gel-drying temperature, annealing time at 900 °C and calcination temperature used in the sol-gel synthesis of Li4Ti5O12 spinel (LTO) on the purity phase, structural and morphological features, and electrochemical properties has been investigated. Synthesized LTO-samples have been characterized by X-ray diffraction and scanning electron microscopy (FE-SEM). High purity LTO-spinels have been synthesized by adjusting the thermal treatment conditions. The rate capability and cycleability of the LTO-samples have been studied by galvanostatic techniques in Li-half cells. The influence of the gel-drying temperature on the LTO-phase purity has been clearly evidenced. Both annealing time and calcination temperature notably modify the morphological features as the particle size, the agglomeration of the particles and its porosity. All the studied LTO-samples show a similar evolution of the capacity vs current in the rate capability test. Cycling studies have shown that LTO-samples exhibit high reversibility. Among the sol-gel synthesized LTO-spinels that prepared after drying the gel precursor at 150 °C, and then annealed at 550 °C for 6 h and 900 °C for 1 h shows the best electrochemical performances. It nominal capacity is 165 m Ah/g and it has a reversible capacity of 87 mA h/g at 1 C (175 mA/g) with no capacity fading after 100 cycles.Financial support through the projects MAT2011-22969 (MINECO), MATERYENER Ref. P2009/PPQ-1626 (CAM) and 2009MA0007 (CSIC/CNRST) and CNRST (Recherche Sectorielle RS03/2011) are gratefully recognized. A. Mahmoud thanks the AECID for the MAEC-AECI fellowship

Electrode Based on Oxyphosphates as Anode Materials for High Energy Density Lithium-ion Batteries

Lithium-ion batteries (Li-ion) are interesting devices for electrochemical energy storage for most emerging green technologies such as wind and solar technologies or hybrid and plug-in electric vehicles or for classical electrical devices such as laptops, phones or other electronic tools. Nevertheless, the oxygen release at high potentials in the present commercialized electrode materials (e.g. LiCoO2) leads to high thermal instability of these oxides and thus to many safety problems. This safety problem is more pronounced for stationary applications for which large size batteries were needed. Polyanionic materials in general, and particularly phosphates were well renowned by their high structural stability which are essential to overcome the above mentioned safety issue. Here, we present the structural and the electrochemical performances of three oxyphosphates M0.5TiOPO4 (M: Ni, Co, Fe). More than 300 mAh/g discharge capacity could be delivered by these phosphates under relatively high cycling rate. The lithium insertion/extraction mechanism is composed from an intercalation process for low lithium content to a conversion mechanism for higher lithium concentration leading to the extrusion of the transition metal M from the structure

Structural and electrochemical properties of the LiCo2/3Ni1/6Mn1/6O2 positive electrode material

Cathode materials play an important role in functioning the operation of lithium-ion batteries . Recently, The layered phases in the series Li[Co(1-2y)]NiyMnyO2 have drawn a lot of attention as alternative cathode materials in Li-ion batteries, and considerable research efforts have been made to understand their structure properties relationship.In this work, we have prepared LiCo2/3Ni1/6Mn1/6O2 via the combustion method at 900°C for 12h. Structural and electrochemical properties of this material were investigated. Rietveld analysis of the XRD pattern shows this compound as having the α-NaFeO2 type structure (S.G. R-3m; a = 2.8388(2) Ǻ; c = 14.1557(1) Ǻ). Figure 1 shows the SEM image of the LiCo2/3Ni1/6Mn1/6O2 particles. The material is characterized by a high homogeneity and a granular shape with an average particles size less than 500nm.The electrochemical tests of the studied cathode shows a good reversibility of the charge/discharge process with a high initial discharge capacity of about 162mAh/g in the 2.7-4.5V range at the C/2 (Figure 2). Lithium extraction from this phase occurs without major structural modifications

LiCo2/3Ni1/6Mn1/6O2 Nanoparticles as Energy Storage Material

Lithium ion batteries are widely used as the most advanced power sources for portables electronic devices. LiCoO2 is at the present the popularly used positive electrode material in commercial Li-ion battery, many efforts have been made to improve the electrochemical performance of LiCoO2 cathode by partial substitution of Co with other elements such as Ni, Mn, Cr ,Al, Mg…Many synthesis methods can be used to prepare electrochemically active compounds. In this work, we explore the combustion method to synthesize LiCo2/3Ni1/6Mn1/6O2 because it is one of the best ways to prepare the nano-size cathode material. Cathode materials with small particles tend to have high initial capacity.Figure 1 shows the SEM image of the LiCo2/3Ni1/6Mn1/6O2 particles. The material is characterized by a high homogeneity and a granular shape with an average particles size less than 500nm.The electrochemical tests of the studied cathode shows a good reversibility of the charge/discharge process in the regimes C/5, C/2 and 1C. XRD diffractograms obtained for various compositions clearly evidenced the conservation of the good crystallinity during cycling. More detailed analysis of crystal structure and extensive electrochemical testing results will be presented

Effect of thermal treatment used in the sol–gel synthesis of Li4Ti5O12 spinel on its electrochemical properties as anode for lithium ion batteries

peer reviewedaudience: researcher, professional, studentAbstract The effect of the gel-drying temperature, annealing time at 900°C and calcination temperature used in the sol–gel synthesis of Li4Ti5O12 spinel (LTO) on the purity phase, structural and morphological features, and electrochemical properties has been investigated. Synthesized LTO-samples have been characterized by X-ray diffraction and scanning electron microscopy (FE-SEM). High purity LTO-spinels have been synthesized by adjusting the thermal treatment conditions. The rate capability and cycleability of the LTO-samples have been studied by galvanostatic techniques in Li-half cells. The influence of the gel-drying temperature on the LTO-phase purity has been clearly evidenced. Both annealing time and calcination temperature notably modify the morphological features as the particle size, the agglomeration of the particles and its porosity. All the studied LTO-samples show a similar evolution of the capacity vs current in the rate capability test. Cycling studies have shown that LTO-samples exhibit high reversibility. Among the sol–gel synthesized LTO-spinels that prepared after drying the gel precursor at 150°C, and then annealed at 550°C for 6h and 900°C for 1h shows the best electrochemical performances. It nominal capacity is 165mAh/g and it has a reversible capacity of 87mAh/g at 1C (175mA/g) with no capacity fading after 100 cycles

A review on LiNixCo1−2xMnxO2 (0.1 ≤ x ≤ 0.33) cathode materials for rechargeable Li-ion batteries

Electrochemical and physical properties of LiNixCo1−2xMnxO2 (0.1 ≤ x ≤ 0.33) electrode materials prepared by self-combustion were investigated. Pure LiNixCo1−2xMnxO2 (x = 0.1, 0.2, 0.33) materials with single phase and R-3 m layered structure were obtained as confirmed by X-ray diffraction. Energy Dispersive Spectroscopy, Scanning Electron Microscopy are commonly used to determine the chemical composition and the distribution of particle size of the three samples. The electrochemical performances of the samples were measured at different current rates in the 3-4.5 V potential range. The studied materials exhibit good discharge capacity. The magnetic susceptibility measurements and conventional electronic paramagnetic resonance spectroscopy (EPR, 9.23 GHz) are coupled to probe the valence state of the transition metal ions and to understand their distributions via their magnetic interactions. X-band EPR spectroscopy has been used to study the local environment in the layered LiNixCo1−2xMnxO2. It has been demonstrated that both Ni2+ and Mn4+ ions are paramagnetic while Co3+ exhibits a diamagnetic low-spin configuration in the starting material

On the LiCo2/3Ni1/6Mn1/6O2 positive electrode material

peer reviewedaudience: researcher, professional, studentAbstract LiCo2/3Ni1/6Mn1/6O2 layered oxide was synthesized by the combustion method that led to a crystalline phase with good homogeneity and low particles size. The structural properties of the prepared positive electrode material were investigated by performing XRD Rietveld refinement. Practically no Li/Ni mixing was detected evidencing that the studied compound adopts almost an ideal α-NaFeO2 type structure. The Li||LiCo2/3Ni1/6Mn1/6O2 cell showed a discharge capacity of 199mAhg−1 when cycled in the 2.7–4.6V potential range while the best cycling performances were recorded when the upper cut off is fixed at 4.5V. Structural changes in LixCo2/3Ni1/6Mn1/6O2 with lithium electrochemical de-intercalation were studied using X-ray diffraction. This study clearly shows the existence of a solid solution domain in the 0.1<x<1.0 composition range while for x=0.1, a new phase appears explaining the decrease of the electrochemical performance when the cell is cycled at high upper cut off voltage