scholarly journals Effect of Electrolyte Anion on Electrochemical Behavior of Nickel Hexacyanoferrate Electrode in Aqueous Sodium-Ion Batteries

2020 ◽  
Vol 58 (12) ◽  
pp. 896-906
Author(s):  
Sungjun Park ◽  
Sang-Eun Chun
Keyword(s):  
Charge Transfer ◽  
Specific Capacity ◽  
Charge Transfer Resistance ◽  
Sodium Ion ◽  
Sodium Ion Batteries ◽  
Atomic Composition ◽  
Rate Performance ◽  
Transfer Resistance ◽  
Nickel Hexacyanoferrate ◽  
Aqueous Sodium

Nickel hexacyanoferrate (NiHCF) has a three-dimensional open framework structure, excellent long-cycling stability and rate performance as a cathode for aqueous sodium-ion batteries. However, the specific capacity of NiHCF is lower than that of present cathodes for aqueous batteries. A sodium-ion electrolyte was explored to achieve optimum capacity with NiHCF. Powder-type NiHCF was fabricated by coprecipitation with the atomic composition K0.065Ni1.44Fe(CN)6·4.4H2O. The presence of Fe vacancies in the atomic composition is attributable to the inclusion of coordinating and zeolitic water during coprecipitation. Two sodium-ion electrolytes, 1 M Na2SO4 and 1 M NaNO3, were employed to analyze the electrochemical behavior of the NiHCF electrode. Identical redox potentials to 0.58 V (vs. NHE) were measured in both electrolytes. However, a lower overpotential was observed in NaNO3 compared to Na2SO4 as a result of the smaller interfacial charge transfer resistance. The lower charge transfer resistance in the NaNO3 solution produced a higher specific capacity of 57 mAh g<sup>-1</sup> (1 C-rate) and the superior capacity retention of 46.6% at 20 C-rate. The anion in the aqueous electrolyte changed the charge transfer resistance at the electrode/electrolyte interface, confirming the electrolyte anion has a crucial effect on the charge capacity and rate performance of NiHCF.

scholarly journals Effect of nanostructured carbon coatings on the electrochemical performance of Li1.4Ni0.5Mn0.5O2+ x -based cathode materials

2016 ◽  
Vol 7 ◽  
pp. 1960-1970 ◽  
Author(s):  
Konstantin A Kurilenko ◽  
Oleg A Shlyakhtin ◽  
Oleg A Brylev ◽  
Dmitry I Petukhov ◽  
Alexey V Garshev
Keyword(s):  
Diffusion Coefficient ◽  
Charge Transfer ◽  
Specific Capacity ◽  
Charge Transfer Resistance ◽  
Poly Vinyl Alcohol ◽  
Nanostructured Carbon ◽  
Transfer Resistance ◽  
Carbon Coatings ◽  
Lithium Diffusion Coefficient ◽  
Electrochemical Cycling

Nanocomposites of Li1.4Ni0.5Mn0.5O2+ x and amorphous carbon were obtained by the pyrolysis of linear and cross-linked poly(vinyl alcohol) (PVA) in presence of Li1.4Ni0.5Mn0.5O2+ x . In the case of linear PVA, the formation of nanostructured carbon coatings on Li1.4Ni0.5Mn0.5O2+ x particles is observed, while for cross-linked PVA islands of mesoporous carbon are located on the boundaries of Li1.4Ni0.5Mn0.5O2+ x particles. The presence of the carbon framework leads to a decrease of the polarization upon cycling and of the charge transfer resistance and to an increase in the apparent Li+ diffusion coefficient from 10−16 cm2·s−1 (pure Li1.4Ni0.5Mn0.5O2+ x ) to 10−13 cm2·s−1. The nanosized carbon coatings also reduce the deep electrochemical degradation of Li1.4Ni0.5Mn0.5O2+ x during electrochemical cycling. The nanocomposite obtained by the pyrolysis of linear PVA demonstrates higher values of the apparent lithium diffusion coefficient, a higher specific capacity and lower values of charge transfer resistance, which can be related to the more uniform carbon coatings and to the significant content of sp2-hybridized carbon detected by XPS and by Raman spectroscopy.

scholarly journals Electrochemical Impedance Spectroscopy on the Performance Degradation of LiFePO4/Graphite Lithium-Ion Battery Due to Charge-Discharge Cycling under Different C-Rates

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4507 ◽  
Author(s):  
Yusuke Abe ◽  
Natsuki Hori ◽  
Seiji Kumagai
Keyword(s):  
Charge Transfer ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Performance Degradation ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Charge Discharge

Lithium-ion batteries (LIBs) using a LiFePO4 cathode and graphite anode were assembled in coin cell form and subjected to 1000 charge-discharge cycles at 1, 2, and 5 C at 25 °C. The performance degradation of the LIB cells under different C-rates was analyzed by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy. The most severe degradation occurred at 2 C while degradation was mitigated at the highest C-rate of 5 C. EIS data of the equivalent circuit model provided information on the changes in the internal resistance. The charge-transfer resistance within all the cells increased after the cycle test, with the cell cycled at 2 C presenting the greatest increment in the charge-transfer resistance. Agglomerates were observed on the graphite anodes of the cells cycled at 2 and 5 C; these were more abundantly produced in the former cell. The lower degradation of the cell cycled at 5 C was attributed to the lowered capacity utilization of the anode. The larger cell voltage drop caused by the increased C-rate reduced the electrode potential variation allocated to the net electrochemical reactions, contributing to the charge-discharge specific capacity of the cells.

Free-Standing NiS2 Electrode as High-Rate Anode Material for Sodium-Ion Batteries

2020 ◽  
Vol 20 (11) ◽  
pp. 7119-7123
Author(s):  
Milan K. Sadan ◽  
Hui Hun Kim ◽  
Changhyeon Kim ◽  
Gyu-Bong Cho ◽  
N. S. Reddy ◽  
...  
Keyword(s):  
Current Density ◽  
Carbon Nanofiber ◽  
High Current Density ◽  
Coulombic Efficiency ◽  
Sodium Ion ◽  
High Rate ◽  
Sodium Ion Batteries ◽  
Rate Performance ◽  
Free Standing ◽  
Transfer Resistance

Owing to the speculated price hike and scarcity of lithium resources, sodium-ion batteries are attracting significant research interest these days. However, sodium-ion battery anodes do not deliver good electrochemical performance, particularly rate performance. Herein, we report the facile electrospinning synthesis of a free-standing nickel disulfide (NiS2) embedded on carbon nanofiber. This electrode did not require a conducting agent, current collector, and binder, and typically delivered high capacity and rate performance. The electrode delivered a high initial capacity of 603 mAh g−1 at the current density of 500 mA g−1. Moreover, the electrode delivered the capacity of 271 mAh g−1 at the high current density of 15 A g−1. The excellent rate performance and high coulombic efficiency of the electrode were attributed to its low charge transfer resistance and unique structure.

scholarly journals FEC Additive for Improved SEI Film and Electrochemical Performance of the Lithium Primary Battery

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7467
Author(s):  
Xuan Zhou ◽  
Ping Li ◽  
Zhihao Tang ◽  
Jialu Liu ◽  
Shaowei Zhang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Electrochemical Performance ◽  
Solid Electrolyte Interphase ◽  
Specific Capacity ◽  
Charge Transfer Resistance ◽  
Anode Surface ◽  
Transfer Resistance ◽  
Metal Anode ◽  
Primary Battery ◽  
Sei Film

The solid electrolyte interphase (SEI) film plays a significant role in the capacity and storage performance of lithium primary batteries. The electrolyte additives are essential in controlling the morphology, composition and structure of the SEI film. Herein, fluoroethylene carbonate (FEC) is chosen as the additive, its effects on the lithium primary battery performance are investigated, and the relevant formation mechanism of SEI film is analyzed. By comparing the electrochemical performance of the Li/AlF3 primary batteries and the microstructure of the Li anode surface under different conditions, the evolution model of the SEI film is established. The FEC additive can decrease the electrolyte decomposition and protect the lithium metal anode effectively. When an optimal 5% FEC is added, the discharge specific capacity of the Li/AlF3 primary battery is 212.8 mAh g−1, and the discharge specific capacities are respectively 205.7 and 122.3 mAh g−1 after storage for 7 days at room temperature and 55 °C. Compared to primary electrolytes, the charge transfer resistance of the Li/AlF3 batteries with FEC additive decreases, indicating that FEC is a promising electrolyte additive to effectively improve the SEI film, increase discharge-specific capacities and promote charge transfer of the lithium primary batteries.

scholarly journals Carbon-Interlayer SnO2–Sb2O3 Composite Core–Shell Structure Anodes for Sodium-Ion Batteries

2021 ◽  
Vol 8 ◽  
Author(s):  
Guoju Zhang ◽  
Yuanduo Qu ◽  
Fanghui Zhao ◽  
Rongxin Dang ◽  
Jie Yang ◽  
...  
Keyword(s):  
Shell Structure ◽  
Specific Capacity ◽  
Hollow Structure ◽  
Rate Capability ◽  
Sodium Ion ◽  
Core Shell ◽  
Discharge Process ◽  
Sodium Ion Batteries ◽  
Rate Performance ◽  
Core Shell Structure

Although great efforts have been dedicated to improving electrochemical property of oxides anode material for sodium-ion batteries, the cycling life and rate capability of oxides anode materials are still far from its theoretical value. Herein, novel uniform SnO2@C@Sb2O3 submicrospheres with multilayer core–shell hollow structure have been synthesized as anode of sodium-ion batteries. The multilayer core–shell structure SnO2@C@Sb2O3 composite delivers a reversible capacity of 269 mAh g−1 at higher current density (1,500 mA g−1) after 100 cycles and exhibited excellent rate performance. The conductivity of the anode composite is promoted by the uniformly carbon dispersion through the whole submicrospheres. The dramatic volume change of electrode material could be mitigated by the porous core–shell structure of Sb2O3 and SnO2 during charge–discharge process. The enhanced specific capacity and rate performance are mainly ascribed to the integrity of structure and synergy effect between different metal oxides.

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