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Secondary Batteries (secondary + battery)

Distribution by Scientific Domains
Polymers and Materials Science87%

Selected Abstracts

Capacity Fading Mechanism in All Solid-State Lithium Polymer Secondary Batteries Using PEG-Borate/Aluminate Ester as Plasticizer for Polymer Electrolytes

ADVANCED FUNCTIONAL MATERIALS, Issue 6 2009
Fuminari Kaneko
Abstract Solid-state lithium polymer secondary batteries (LPB) are fabricated with a two-electrode-type cell construction of Li|solid-state polymer electrolyte (SPE)|LiFePO4. Plasticizers of poly(ethylene glycol) (PEG)-borate ester (B-PEG) or PEG-aluminate ester (Al-PEG) are added into lithium-conducting SPEs in order to enhance their ionic conductivity, and lithium bis-trifluoromethansulfonimide (LiTFSI) is used as the lithium salt. An improvement of the electrochemical properties is observed upon addition of the plasticizers at an operation temperature of 60,°C. However, a decrease of discharge capacities abruptly follows after tens of stable cycles. To understand the origin of the capacity fading, electrochemical impedance techniques, ex-situ NMR and scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS) techniques are adopted. Alternating current (AC) impedance measurements indicate that the decrease of capacity retention in the LPB is related to a severe increase of the interfacial resistance between the SPE and cathode. In addition, the bulk resistance of the SPE film is observed to accompany the capacity decay. Ex situ NMR studies combined with AC impedance measurements reveal a decrease of Li salt concentration in the SPE film after cycling. Ex situ SEM/EDS observations show an increase of concentration of anions on the electrode surface after cycling. Accordingly, the anions may decompose on the cathode surface, which leads to a reduction of the cycle life of the LPB. The present study suggests that a choice of Li salt and an increase of transference number is crucial for the realization of lithium polymer batteries. [source]

Conducting-Polymer/Iron-Redox- Couple Composite Cathodes for Lithium Secondary Batteries,

ADVANCED MATERIALS, Issue 6 2007
K.-S. Park
Physically or chemically attaching an FeIII/FeIIredox couple to the backbone of a conducting polymer leads to stabilization of the charge/discharge characteristics and higher electrode capacities. Composite cathodes made from LiFePO4 particles bound to polypyrrole show enhanced electrode capacities and better rate capabilities, as shown in the figure. Chemically attaching ferrocene to the pyrrole backbone not only stabilizes the charge,discharge curves but also leads to higher capacity. [source]

All Solid-State Lithium Secondary Batteries Using High Lithium Ion Conducting Li2S,P2S5 Glass-Ceramics.

CHEMINFORM, Issue 13 2003
Fuminori Mizuno
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Capacity Fading Mechanism in All Solid-State Lithium Polymer Secondary Batteries Using PEG-Borate/Aluminate Ester as Plasticizer for Polymer Electrolytes

ADVANCED FUNCTIONAL MATERIALS, Issue 6 2009
Fuminari Kaneko
Abstract Solid-state lithium polymer secondary batteries (LPB) are fabricated with a two-electrode-type cell construction of Li|solid-state polymer electrolyte (SPE)|LiFePO4. Plasticizers of poly(ethylene glycol) (PEG)-borate ester (B-PEG) or PEG-aluminate ester (Al-PEG) are added into lithium-conducting SPEs in order to enhance their ionic conductivity, and lithium bis-trifluoromethansulfonimide (LiTFSI) is used as the lithium salt. An improvement of the electrochemical properties is observed upon addition of the plasticizers at an operation temperature of 60,°C. However, a decrease of discharge capacities abruptly follows after tens of stable cycles. To understand the origin of the capacity fading, electrochemical impedance techniques, ex-situ NMR and scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS) techniques are adopted. Alternating current (AC) impedance measurements indicate that the decrease of capacity retention in the LPB is related to a severe increase of the interfacial resistance between the SPE and cathode. In addition, the bulk resistance of the SPE film is observed to accompany the capacity decay. Ex situ NMR studies combined with AC impedance measurements reveal a decrease of Li salt concentration in the SPE film after cycling. Ex situ SEM/EDS observations show an increase of concentration of anions on the electrode surface after cycling. Accordingly, the anions may decompose on the cathode surface, which leads to a reduction of the cycle life of the LPB. The present study suggests that a choice of Li salt and an increase of transference number is crucial for the realization of lithium polymer batteries. [source]

Template-Free Synthesis of SnO2 Hollow Nanostructures with High Lithium Storage Capacity,

ADVANCED MATERIALS, Issue 17 2006
W. Lou
A facile one-step template-free method based on a novel inside-out Ostwald ripening mechanism is developed for inexpensive mass preparation of hollow and hollow core/shell-type SnO2 nanostructures using potassium stannate as the precursor. As-prepared SnO2 hollow nanospheres (see figure) exhibit ultrahigh lithium storage capacity and improved cycle performance as high-energy anode materials in lithium-ion secondary batteries. [source]

A study on the behavior of a cylindrical type Li-Ion secondary battery under abnormal conditions. Über das Verhalten eines zylindrischen Li-Ionen Akkumulators unter abnormalen Bedingungen

MATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 5 2010
S. Kim
zylindrische Li-Ionen Akkumulatoren; mechanisches Verhalten; abnormale Bedingungen; Separator Abstract Li-ion (lithium ion) secondary batteries are rechargeable batteries in which lithium ions move between the cathode and the anode. Lithium is not as safe as nickel cadmium (NiCd), and the Li-ion battery can under some conditions increase in temperature and ignite abnormal conditions which includes overcharging, being subjected to an impact, or being hit by a projectile. Before studying causes of Li-ion battery explosions, the term "abnormal condition" was defined. Next, to check the mechanical conditions, an impact test by a free falling object of 9.1 kg weight made of steel was carried out. After the impact test, the damage of the separator around the hollow of the jelly roll in the cell was observed. Following this, the same cell's electrochemical conditions were assessed through a heating test to determine the potential thermal runaway. Finally, to analyze the mechanical damage to the Li-ion batteries during the charging and the impact test, a finite element analysis was performed using LS-DYNA and ABAQUS software. A cylindrical type Li-ion secondary battery was selected for the impact test, heating test, and simulation. The test and simulation results provided insights into the extent to which cylindrical cells can endure abnormal conditions. [source]