scholarly journals Synthesis of High Surface Area α-KyMnO2 Nanoneedles Using Extract of Broccoli as Bioactive Reducing Agent and Application in Lithium Battery

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1269 ◽  
Author(s):  
Ahmed Hashem ◽  
Hanaa Abuzeid ◽  
Martin Winter ◽  
Jie Li ◽  
Christian Julien
Keyword(s):  
Surface Area ◽  
Coulombic Efficiency ◽  
High Surface ◽  
High Surface Area ◽  
Rate Capability ◽  
Lithium Ion ◽  
Reducing Agent ◽  
Capacity Retention ◽  
Transmission Electron ◽  
Initial Capacity

With the aim to reduce the entire cost of lithium-ion batteries and to diminish the environmental impact, the extract of broccoli is used as a strong benign reducing agent for potassium permanganate to synthesize α-KyMnO2 cathode material with pure nanostructured phase. Material purity is confirmed by X-ray powder diffraction and thermogravimetric analyses. Images of transmission electron microscopy show samples with a spider-net shape consisting of very fine interconnected nanoneedles. The nanostructure is characterized by crystallite of 4.4 nm in diameter and large surface area of 160.7 m2 g−1. The material delivers an initial capacity of 211 mAh g−1 with high Coulombic efficiency of 99% and 82% capacity retention after 100 cycles. Thus, α-KyMnO2 synthesized via a green process exhibits very promising electrochemical performance in terms of initial capacity, cycling stability and rate capability.

Texture Evaluation of Sol-Gel Derived Mesoporous Bioactive Glass

2013 ◽  
Vol 284-287 ◽  
pp. 230-234
Author(s):  
Yu Jen Chou ◽  
Chi Jen Shih ◽  
Shao Ju Shih
Keyword(s):  
Surface Area ◽  
Calcination Temperature ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Bioactive Glasses ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Adsorption Desorption

Recent years mesoporous bioactive glasses (MBGs) have become important biomaterials because of their high surface area and the superior bioactivity. Various studies have reported that when MBGs implanted in a human body, hydroxyl apatite layers, constituting the main inorganic components of human bones, will form on the MBG surfaces to increase the bioactivity. Therefore, MBGs have been widely applied in the fields of tissue regeneration and drug delivery. The sol-gel process has replaced the conventional glasses process for MBG synthesis because of the advantages of low contamination, chemical flexibility and lower calcination temperature. In the sol-gel process, several types of surfactants were mixed with MBG precursor solutions to generate micelle structures. Afterwards, these micelles decompose to form porous structures after calcination. Although calcination is significant for contamination, crystalline and surface area in MBG, to the best of the authors’ knowledge, only few systematic studies related to calcination were reported. This study correlated the calcination parameters and the microstructure of MBGs. Microstructure evaluation was characterized by transmission electron microscopy and nitrogen adsorption/desorption. The experimental results show that the surface area and the pore size of MBGs decreased with the increasing of the calcination temperature, and decreased dramatically at 800°C due to the formation of crystalline phases.

scholarly journals Synthesis of Hierarchical Graphene-MnO2 Nanowire Composites with Enhanced Specific Capacitance

2019 ◽  
Vol 31 (8) ◽  
pp. 1709-1718
Author(s):  
T. Veldevi ◽  
K. Thileep Kumar ◽  
R.A. Kalaivani ◽  
S. Raghu ◽  
A.M. Shanmugharaj
Keyword(s):  
Surface Area ◽  
Electrode Materials ◽  
High Surface ◽  
Specific Capacity ◽  
High Surface Area ◽  
Rate Capability ◽  
Sulfate Solution ◽  
High Rate ◽  
Chemical Compositions ◽  
Structure Morphology

Hierarchical nanostructured graphene–manganese dioxide nanowire (G-MnO2-NW) composites have been prepared by hydrothermal synthesis route using water/1-decanol as the medium. Synthesized materials were analyzed using various characterization tools to corroborate their chemical compositions, structure/morphology and surface area. Electrochemical measurements of the synthesized G-MnO2-NW electrode materials delivered the highest specific capacity (255 Fg-1), high rate capability and improved cycling stability at 0.5 Ag–1 in 1M sodium sulfate solution and this fact may be attributed to its high surface area and porosity. Moreover, synthesized G-MnO2-NW electrodes displayed better energy and power density, when compared to the MnO2-NW based electrodes.

scholarly journals Tailoring of Aqueous-Based Carbon Nanotube–Nanocellulose Films as Self-Standing Flexible Anodes for Lithium-Ion Storage

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 655 ◽  
Author(s):  
Hoang Kha Nguyen ◽  
Jaehan Bae ◽  
Jaehyun Hur ◽  
Sang Joon Park ◽  
Min Sang Park ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
High Surface ◽  
High Surface Area ◽  
Composite Films ◽  
Rate Capability ◽  
Morphological Characteristics ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
High Rate ◽  
Voltage Profile

An easy and environmentally friendly method was developed for the preparation of a stabilized carbon nanotube–crystalline nanocellulose (CNT–CNC) dispersion and for its deposition to generate self-standing CNT–CNC composite films. The composite films were carbonized at different temperatures of 70 °C, 800 °C, and 1300 °C. Structural and morphological characteristics of the CNT–CNC films were investigated by X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM), which revealed that the sample annealed at 800 °C (CNT–CNC800) formed nano-tree networks of CNTs with a high surface area (1180 m2·g−1) and generated a conductive CNC matrix due to the effective carbonization. The carbonized composite films were applied as anodes for lithium-ion batteries, and the battery performance was evaluated in terms of initial voltage profile, cyclic voltammetry, capacity, cycling stability, and current rate efficiency. Among them, the CNT–CNC800 anode exhibited impressive electrochemical performance by showing a reversible capacity of 443 mAh·g−1 at a current density of 232 mA·g−1 after 120 cycles with the capacity retention of 89% and high rate capability.

Hierarchically porous and nitrogen, sulfur-codoped graphene-like microspheres as a high capacity anode for lithium ion batteries

2015 ◽  
Vol 51 (11) ◽  
pp. 2134-2137 ◽  
Author(s):  
Dongfei Sun ◽  
Juan Yang ◽  
Xingbin Yan
Keyword(s):  
Lithium Ion Batteries ◽  
Surface Area ◽  
Anode Material ◽  
High Surface ◽  
High Surface Area ◽  
High Capacity ◽  
Lithium Ion ◽  
The Novel ◽  
Heteroatom Doping ◽  
Hierarchically Porous

The novel hierarchically porous and nitrogen, sulfur-codoped graphene-like microspheres are constructed as the anode material for lithium ion batteries. High surface area and efficient heteroatom doping provide high capacity and enhanced cycling stability.

Organic salt-derived nitrogen-rich, hierarchical porous carbon for ultrafast supercapacitors

2017 ◽  
Vol 41 (22) ◽  
pp. 13611-13618 ◽  
Author(s):  
Longfeng Hu ◽  
Li Ma ◽  
Qizhen Zhu ◽  
Lanyong Yu ◽  
Qi Wu ◽  
...  
Keyword(s):  
Surface Area ◽  
Porous Carbon ◽  
High Surface ◽  
High Surface Area ◽  
Rate Capability ◽  
Organic Salt ◽  
Porous Carbons ◽  
Hierarchical Porous Carbon ◽  
Hierarchical Porous ◽  
Hierarchical Porous Carbons

Nitrogen-rich, high surface area, hierarchical porous carbons were simply prepared by the pyrolysis of a nitrogen-containing organic salt, and exhibit excellent rate capability in supercapacitors.

Reduction of bis(Oxalato)Borate on a High Surface Area Carbon Electrode

2008 ◽  
Vol 1127 ◽  
Author(s):  
John Flynn ◽  
Carl Schlaikjer
Keyword(s):  
Surface Area ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Lithium Ion ◽  
Potential Range ◽  
Electrolytic Properties ◽  
Extensive Exchange ◽  
Soluble Species ◽  
Wide Potential

ABSTRACTLithium bis(oxalato)borate (LiBOB) has gained widespread interest as an electrolyte salt for lithium ion batteries because of its high conductivity, low cost, thermal stability, and adequate solubility in many organic solvents [1]. Cyclic voltammetric data taken on platinum [2] and carbon [3] indicate electrochemical stability over a wide potential range.We show that bis(oxalato)borate (BOB) can be reduced at about 1.75 volts anodic to lithium, by discharging electrolytes at low current density (0.1 mA/cm2) on high surface area carbon electrodes containing a mixture of acetylene and Ketjen carbon blacks. The evidence includes discharge profiles and 11B NMR data. The behavior of discharge plateaus indicates that BOB is reduced to a soluble species with electrolytic properties, and the appearance of a broad 11B NMR peak in the electrolyte indicates that the reduced species undergoes extensive exchange.

scholarly journals Li2O-Based Cathode Additives Enabling Prelithiation of Si Anodes

2021 ◽  
Vol 11 (24) ◽  
pp. 12027
Author(s):  
Yeyoung Ha ◽  
Maxwell C. Schulze ◽  
Sarah Frisco ◽  
Stephen E. Trask ◽  
Glenn Teeter ◽  
...  
Keyword(s):  
Coulombic Efficiency ◽  
High Surface ◽  
Solid Electrolyte Interphase ◽  
Active Material ◽  
High Surface Area ◽  
Lithium Ion ◽  
Particle Morphology ◽  
Lithium Oxide ◽  
Si Anodes ◽  
The Impact

Low first-cycle Coulombic efficiency is especially poor for silicon (Si)-based anodes due to the high surface area of the Si-active material and extensive electrolyte decomposition during the initial cycles forming the solid electrolyte interphase (SEI). Therefore, developing successful prelithiation methods will greatly benefit the development of lithium-ion batteries (LiBs) utilizing Si anodes. In pursuit of this goal, in this study, lithium oxide (Li2O) was added to a LiNi0.6Mn0.2Co0.2O2 (NMC622) cathode using a scalable ball-milling approach to compensate for the initial Li loss at the anode. Different milling conditions were tested to evaluate the impact of particle morphology on the additive performance. In addition, Co3O4, a well-known oxygen evolution reaction catalyst, was introduced to facilitate the activation of Li2O. The Li2O + Co3O4 additives successfully delivered an additional capacity of 1116 mAh/gLi2O when charged up to 4.3 V in half cells and 1035 mAh/gLi2O when charged up to 4.1 V in full cells using Si anodes.

Free-Supporting Dual-Confined Porous Si@c-ZIF@carbon nanofibers for high-performance lithium-ion batteries

2021 ◽  
Author(s):  
Jiale Chen ◽  
Xingmei Guo ◽  
Mingyue Gao ◽  
Jing Wang ◽  
Shangqing Sun ◽  
...  
Keyword(s):  
Antioxidant Capacity ◽  
Lithium Ion Batteries ◽  
Surface Area ◽  
Carbon Nanofibers ◽  
Volume Expansion ◽  
High Performance ◽  
High Surface ◽  
High Surface Area ◽  
Lithium Ion ◽  
Porous Si

Dual-confined porous Si@c-ZIF@carbon nanofibers (Si@c-ZIF@CNFs) are fabricated, possessing excellent antioxidant capacity, high surface area and abundant pores, which availably enhance conductivity, relieve volume expansion and facilitate electrolyte penetration during cycling....

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