scholarly journals Structural and Electrochemical Properties of the High Ni Content Spinel LiNiMnO4

Electrochem ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 95-117
Author(s):  
Tianyi Li ◽  
Kai Chang ◽  
Ahmed M. Hashem ◽  
Ashraf E. Abdel-Ghany ◽  
Rasha S. El-Tawil ◽  
...  
Keyword(s):  
Sol Gel ◽  
Specific Capacity ◽  
Secondary Phase ◽  
Cubic Phase ◽  
Electrochemical Performances ◽  
Rietveld Refinements ◽  
Selected Area Electron Diffraction ◽  
V Region ◽  
Spinel Cathode

This work presents a contribution to the study of a new Ni-rich spinel cathode material, LiNiMnO4, for Li-ion batteries operating in the 5-V region. The LiNiMnO4 compound was synthesized by a sol-gel method assisted by ethylene diamine tetra-acetic acid (EDTA) as a chelator. Structural analyses carried out by Rietveld refinements and Raman spectroscopy, selected area electron diffraction (SAED) and X-ray photoelectron (XPS) spectroscopy reveal that the product is a composite (LNM@NMO), including non-stoichiometric LiNiMnO4-δ spinel and a secondary Ni6MnO8 cubic phase. Cyclic voltammetry and galvanostatic charge-discharge profiles show similar features to those of LiNi0.5Mn1.5O4 bare. A comparison of the electrochemical performances of 4-V spinel LiMn2O4 and 5-V spinel LiNi0.5Mn1.5O4 with those of LNM@NMO composite demonstrates the long-term cycling stability of this new Ni-rich spinel cathode. Due to the presence of the secondary phase, the LNM@NMO electrode exhibits an initial specific capacity as low as 57 mAh g−1 but shows an excellent electrochemical stability at 1C rate for 1000 cycles with a capacity decay of 2.7 × 10−3 mAh g−1 per cycle.

FACILE SOL–GEL SYNTHESIS OF Li[Li0.2Mn0.56Ni0.16Co0.08]O2 AS IMPROVED CATHODE MATERIAL FOR LITHIUM-ION BATTERIES

2013 ◽  
Vol 01 (04) ◽  
pp. 1340015
Author(s):  
WENJUAN HAO ◽  
HAN CHEN ◽  
YANHONG WANG ◽  
HANHUI ZHAN ◽  
QIANGQIANG TAN ◽  
...  
Keyword(s):  
Cathode Materials ◽  
Sol Gel ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Electrochemical Performances ◽  
Acetate Tetrahydrate ◽  
Li Ion Batteries ◽  
Gel Method ◽  
Sol Gel Method ◽  
Li Ion

Li [ Li 0.2 Mn 0.56 Ni 0.16 Co 0.08] O 2 cathode materials for Li -ion batteries were synthesized by a facile sol–gel method followed by calcination at various temperatures (700°C, 800°C and 900°C). Lithium acetate dihydrate, manganese (II) acetate tetrahydrate, nickel (II) acetate tetrahydrate and cobalt (II) acetate tetrahydrate are employed as the metal precursors, and citric acid monohydrate as the chelating agent. For the obtained Li [ Li 0.2 Mn 0.56 Ni 0.16 Co 0.08] O 2 materials, the metal components existed in the form of Mn 4+, Ni 2+ and Co 3+, and their molar ratio was in good agreement with 0.56 : 0.16 : 0.08. The calcination temperature played an important role in the particle size, crystallinity and further electrochemical properties of the cathode materials. The Li [ Li 0.2 Mn 0.56 Ni 0.16 Co 0.08] O 2 material calcined at 800°C for 6 h showed the best electrochemical performances. Its discharge specific capacities cycled at 0.1 C, 0.5 C, 1 C and 2 C rates were 266.0 mAh g−1, 243.1 mAh g−1, 218.2 mAh g−1 and 192.9 mAh g−1, respectively. When recovered to 0.1 C rate, the discharge specific capacity was 260.2 mAh g−1 and the capacity loss is only 2.2%. This work demonstrates that the sol–gel method is a facile route to prepare high performance Li [ Li 0.2 Mn 0.56 Ni 0.16 Co 0.08] O 2 cathode materials for Li -ion batteries.

TiNb2O7 nanorods as a novel anode material for secondary lithium-ion batteries

2016 ◽  
Vol 09 (06) ◽  
pp. 1642004 ◽  
Author(s):  
Lei Hu ◽  
Chunfu Lin ◽  
Changhao Wang ◽  
Chao Yang ◽  
Jianbao Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Average Length ◽  
Sol Gel ◽  
Specific Capacity ◽  
Sodium Dodecyl ◽  
Rate Capability ◽  
Lithium Ion ◽  
Average Diameter ◽  
Electrochemical Performances ◽  
Text Type

TiNb2O7 nanorods have been successfully fabricated by a sol–gel method with a sodium dodecyl surfate (SDS) surfactant. X-ray diffraction indicates that the TiNb2O7 nanorods have a Ti2Nb[Formula: see text]O[Formula: see text]-type crystal structure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results show that the nanorods have an average diameter of [Formula: see text][Formula: see text]100[Formula: see text]nm and an average length of [Formula: see text][Formula: see text]300[Formula: see text]nm. As a result of such nanosizing effect, this new material exhibits advanced electrochemical performances in terms of specific capacity, rate capability and cyclic stability. At 0.1[Formula: see text]C, it delivers a large first-cycle discharge/charge capacity of 337/279 mAh g[Formula: see text]. Its capacities remain 248, 233, 214, 182, 154 and 122[Formula: see text]mAh g[Formula: see text] at 0.5, 1, 2, 5, 10 and 20[Formula: see text]C, respectively. After 100 cycles, its capacity at 10[Formula: see text]C remains 140[Formula: see text]mAh g[Formula: see text] with large capacity retention of 91.0%.

Synthesis and electrochemical properties of SrWO4/graphene composite as anode material for lithium-ion batteries

2014 ◽  
Vol 07 (02) ◽  
pp. 1450010 ◽  
Author(s):  
Linsen Zhang ◽  
Qingling Bai ◽  
Linzhen Wang ◽  
Aiqin Zhang ◽  
Yong Zhang ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Sol Gel ◽  
Specific Capacity ◽  
Rate Capability ◽  
Lithium Ion ◽  
Cycle Performance ◽  
Electrochemical Performances ◽  
Graphene Composite ◽  
Discharge Method ◽  
Charge Discharge

SrWO 4/graphene composite was synthesized via a sol–gel method. The morphology and structure of the products were analyzed by SEM, TEM and XRD. The electrochemical performances of SrWO 4/graphene composite were investigated by galvanostatic charge/discharge method, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that the first cycle of the reversible specific capacity of SrWO 4/graphene composite can reach to 575.9 mAh g-1 at 50 mA g-1. The charge/discharge cycling study indicates that the SrWO 4/graphene composite was provided with excellent cycle performance and outstanding rate capability.

Preparation and Characterization of Sol–Gel-Driven LixLa3Zr2O12 Solid Electrolytes and LiCoO2 Cathodes for All-Solid-State Lithium-Ion Batteries

2020 ◽  
Vol 20 (11) ◽  
pp. 7002-7009
Author(s):  
Gwan Hyeon Kim ◽  
Min Ji Kim ◽  
Hae Been Kim ◽  
Ji Heon Ryu ◽  
Hee Chul Lee
Keyword(s):  
Solid State ◽  
Solid Electrolyte ◽  
Sol Gel ◽  
Lithium Ion ◽  
Secondary Phase ◽  
Cubic Phase ◽  
Lithium Content ◽  
Metal Anode ◽  
Garnet Phase ◽  
Step Heat Treatment

In the current study, we prepared a LixLa3Zr2O12 ((Al, Ta) LLZO) powder doped with 0.2 mol of Al and Ta using the sol-gel method and subsequently used it to fabricate solid electrolyte pellets. In pellets with lithium content of 6.2 and 6.82 mol, a cubic phase and a lithium-deficient pyrochlore mixed-phase were respectively observed. However, when the lithium content was 8.06 mol, a lithium-excess phase was also observed. Meanwhile, at 7.44 mol lithium, the (Al, Ta) LLZO ceramic pellets showed a pure cubic garnet phase with no secondary phase. When lithium was added excessively, a non-granular morphology was observed at the (Al, Ta) LLZO fracture surface in which the grains were tightly bonded by the liquid phase formed during sintering. Nyquist plots of the pellets showed that the effect of grain boundaries was eliminated and the pellets exhibited a high lithium ion conductivity of 4.26 × 10−4 S/cm. Using spin coating and multi-step heat treatment, we deposited LiCoO2 (LCO) thin films on (Al, Ta) LLZO pellets to form cathodes. There was no significant interdiffusion between the LCO cathode and (Al, Ta) LLZO solid electrolyte and morphological analysis indicted that a thin interfacial layer (~10 nm) was formed between the LCO and the electrolyte. Finally, we demonstrated an all-solid-state rechargeable battery in the form of a coin cell comprising of an LCO cathode, Li metal anode, and (Al, Ta) LLZO solid electrolyte, which could yield a discharge capacity of ~100 mAh/g.

scholarly journals From tunnel NMO to layered polymorphs oxides for sodium ion batteries

2020 ◽  
Vol 2 (11) ◽  
Author(s):  
Michele Nuti ◽  
Daniele Spada ◽  
Irene Quinzeni ◽  
Stefano Capelli ◽  
Benedetta Albini ◽  
...  
Keyword(s):  
Sodium Ion ◽  
Layered Compounds ◽  
Electrochemical Performances ◽  
Capacity Retention ◽  
Rietveld Refinements ◽  
Sodium Batteries ◽  
Jahn Teller ◽  
Complex Structural ◽  
Fe Ions

AbstractThe search for highly performing cathode materials for sodium batteries is a fascinating topic. Unfortunately, Na0.44MnO2 (NMO), the well-known cathode material with good electrochemical performances, suffers from structural degradation due to reduction of Mn4+ to the Jahn–Teller Mn3+ ion, limiting the long-term cyclability. The cation substitution can be a useful way to mitigate the problem, thanks to the possible stabilization of mixtures of different polymorphs. In this paper, NMO was first substituted with Fe ions, obtaining Na0.44Mn0.5Fe0.5O2, with layered structure, then Al, Si and Cu (10% atom) were substituted on both Mn and Fe ions. Mixtures of P3 type phases, in different amount depending on dopant, were obtained and quantified by Rietveld refinements, and relationships between chemical composition, polymorph type and morphology were proposed. Cyclic voltammetry showed broad peaks, due to the complex structural transitions consequent to the intercalation/deintercalation of sodium. Charge discharge cycles disclosed the superior performances of Cu doped sample, which also benefits from improved air stability, a well-known issue of layered compounds. Discharge capacity values of about 63 mAh/g were detected at 1C, and after 50 cycles at C/2, capacities of about 80 mAh/g are obtained, with a capacity retention of 86%.

scholarly journals Enhancing the Electrochemical Properties of LaCoO3 by Sr-Doping, rGO-Compounding with Rational Design for Energy Storage Device

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Bin Zhang ◽  
Chuanfu Yu ◽  
Zijiong Li
Keyword(s):  
Energy Storage ◽  
Electrochemical Properties ◽  
Rational Design ◽  
Sol Gel ◽  
Specific Capacity ◽  
Functional Materials ◽  
High Energy ◽  
High Energy Density ◽  
Storage Device ◽  
Electrochemical Performances

Abstract Perovskite oxides, as a kind of functional materials, have been widely studied in recent years due to its unique physical, chemical, and electrical properties. Here, we successfully prepared perovskite-type LaCoO3 (LCOs) nanomaterials via an improved sol-gel method followed by calcination, and investigated the influence of calcination temperature and time on the morphology, structure, and electrochemical properties of LaCoO3 nanomaterials. Then, based on the optimal electrochemical performance of LCO-700-4 electrode sample, the newly synthesized nanocomposites of Sr-doping (LSCO-0.2) and rGO-compounding (rGO@LCO) through rational design exhibited a 1.45-fold and 2.03-fold enhancement in its specific capacitance (specific capacity). The rGO@LCO electrode with better electrochemical performances was further explored by assembling rGO@LCO//rGO asymmetric supercapacitor system (ASS) with aqueous electrolyte. The result showed that the ASS delivers a high energy density of 17.62 W h kg−1 and an excellent cyclic stability with 94.48% of initial capacitance after 10,000 cycles, which are good electrochemical performances among aqueous electrolytes for green and new efficient energy storage devices.

scholarly journals Tri-Doping of Sol–Gel Synthesized Garnet-Type Oxide Solid-State Electrolyte

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 134
Author(s):  
Minji Kim ◽  
Gwanhyeon Kim ◽  
Heechul Lee
Keyword(s):  
Solid State ◽  
Sol Gel ◽  
Secondary Phase ◽  
Grain Structure ◽  
Cubic Phase ◽  
Li Ion Batteries ◽  
Li Ion ◽  
Solid State Electrolytes ◽  
Improved Performance ◽  
Cation Sites

The rapidly growing Li-ion battery market has generated considerable demand for Li-ion batteries with improved performance and stability. All-solid-state Li-ion batteries offer promising safety and manufacturing enhancements. Herein, we examine the effect of substitutional doping at three cation sites in garnet-type Li7La3Zr2O12 (LLZO) oxide ceramics produced by a sol–gel synthesis technique with the aim of enhancing the properties of solid-state electrolytes for use in all-solid-state Li-ion batteries. Building on the results of mono-doping experiments with different doping elements and sites—Al, Ga, and Ge at the Li+ site; Rb at the La3+ site; and Ta and Nb at the Zr4+ site—we designed co-doped (Ga, Al, or Rb with Nb) and tri-doped (Ga or Al with Rb and Nb) samples by compositional optimization, and achieved a LLZO ceramic with a pure cubic phase, almost no secondary phase, uniform grain structure, and excellent Li-ion conductivity. The findings extend the current literature on the doping of LLZO ceramics and highlight the potential of the sol–gel method for the production of solid-state electrolytes.

scholarly journals In-Situ Annealed Ti3C2Tx MXene Based All-Solid-State Flexible Zn-Ion Hybrid Micro Supercapacitor Array with Enhanced Stability

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
La Li ◽  
Weijia Liu ◽  
Kai Jiang ◽  
Di Chen ◽  
Fengyu Qu ◽  
...  
Keyword(s):  
High Energy ◽  
High Rate ◽  
High Energy Density ◽  
Electrochemical Performances ◽  
Integrated Electronics ◽  
Long Term Stability ◽  
Hybrid Supercapacitors ◽  
Portable Electronics

AbstractZn-ion hybrid supercapacitors (SCs) are considered as promising energy storage owing to their high energy density compared to traditional SCs. How to realize the miniaturization, patterning, and flexibility of the Zn-ion SCs without affecting the electrochemical performances has special meanings for expanding their applications in wearable integrated electronics. Ti3C2Tx cathode with outstanding conductivity, unique lamellar structure and good mechanical flexibility has been demonstrated tremendous potential in the design of Zn-ion SCs, but achieving long cycling stability and high rate stability is still big challenges. Here, we proposed a facile laser writing approach to fabricate patterned Ti3C2Tx-based Zn-ion micro-supercapacitors (MSCs), followed by the in-situ anneal treatment of the assembled MSCs to improve the long-term stability, which exhibits 80% of the capacitance retention even after 50,000 charge/discharge cycles and superior rate stability. The influence of the cathode thickness on the electrochemical performance of the MSCs is also studied. When the thickness reaches 0.851 µm the maximum areal capacitance of 72.02 mF cm−2 at scan rate of 10 mV s−1, which is 1.77 times higher than that with a thickness of 0.329 µm (35.6 mF cm−2). Moreover, the fabricated Ti3C2Tx based Zn-ion MSCs have excellent flexibility, a digital timer can be driven by the single device even under bending state, a flexible LED displayer of “TiC” logo also can be easily lighted by the MSC arrays under twisting, crimping, and winding conditions, demonstrating the scalable fabrication and application of the fabricated MSCs in portable electronics.

scholarly journals Photocatalytic Activity Enhancement of Low-pressure Cold-Sprayed TiO2 Coatings Induced by Long-term Water Vapor Exposure

2021 ◽  
Author(s):  
Seremak Wioletta ◽  
Baszczuk Agnieszka ◽  
Jasiorski Marek ◽  
Gibas Anna ◽  
Winnicki Marcin
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Water Vapor ◽  
Sol Gel ◽  
Low Pressure ◽  
Oxygen Depletion ◽  
Amorphous Structure ◽  
Industrial Applications ◽  
Additional Parameter

AbstractThis work shows that the titanium dioxide coatings obtained by low-pressure cold gas spraying with the use of the sol–gel amorphous TiO2 powder are characterized by photocatalytic activity despite their partial amorphous content. Moreover, the research outcome suggests that the decomposition rate of organic pollutants is enhanced after long-term exposure to moisture. The condensation humidity test is not detrimental to the continuity and integrity of the coating, but the phase composition of coatings changes—with the exposure to water vapor, the portion of the amorphous phase crystallizes into brookite. The mechanism responsible for the conversion of amorphous TiO2 into brookite is attributed to the water-driven dissolution and reprecipitation of TiO6 octahedra. It has been shown that an additional parameter necessary for the stabilization of the brookite is the oxygen depletion of the amorphous structure of titanium dioxide. Considering the results presented in this paper and the advantages of a portable, low-pressure cold spray system for industrial applications, it is expected that TiO2 coatings produced from a sol–gel feedstock powder can be further developed and tested as efficient photocatalysts.

Sign in / Sign up

Export Citation Format

Share Document