scholarly journals Magnesium Insertion and Related Structural Changes in Spinel-Type Manganese Oxides

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 984
Author(s):  
Ana Robba ◽  
Elena Tchernychova ◽  
Jan Bitenc ◽  
Anna Randon-Vitanova ◽  
Robert Dominko
Keyword(s):  
Electrolyte Solution ◽  
Manganese Oxides ◽  
Structural Changes ◽  
Specific Capacity ◽  
Base Material ◽  
Structural Rearrangement ◽  
Cycling Performance ◽  
Capacity Fading ◽  
Spinel Type ◽  
Hand Cycling

Commercial LiMn2O4 powder was used as the base material for probing magnesiation, cycling behavior, and structural stability/changes in (MgxLi1-x)Mn2O4 spinel cathodes in aqueous Mg(NO3)2 and non-aqueous Mg(TFSI)2/diglyme and Mg(Mg(HFIP)2 − 2Al(HFIP)3/diglyme electrolytes. Each of the samples was delithiated and, then, magnesiated electrochemically in the corresponding electrolyte. The electrochemical activity of the cathode cycled in aqueous electrolyte showed high reversibility during the oxidation process; however, large polarization and a relatively fast capacity fading were the culprits of the system. Cycling in Mg(TFSI)2/diglyme electrolyte solution resulted in much lower initial specific capacity compared to an aqueous counterpart, as well as a much faster failure. On the other hand, cycling in Mg(HFIP)2 − 2Al(HFIP)3/diglyme electrolyte solution demonstrated excellent cycling performance with very low polarization in the first cycles. The observed voltages for this system were near theoretical values for the Mg insertion. Although the electrochemical measurements suggest reversible magnesiation, detailed structural and analytical STEM investigation revealed the differences in the atomic structure and Mn valence of all three cathode samples upon cycling. The electrolytes’ influence on the structural rearrangement during Mg insertion is discussed for each of the three systems.

Controlling the Voltage Window for Improved Cycling Performance of SnO2 as Anode Material for Lithium-Ion Batteries

2020 ◽  
Vol 20 (11) ◽  
pp. 7051-7056
Author(s):  
Jungwon Heo ◽  
Anupriya K. Haridas ◽  
Xueying Li ◽  
Rakesh Saroha ◽  
Younki Lee ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Anode Material ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Cycling Performance ◽  
Oxide Materials ◽  
Capacity Fading ◽  
Lithium Ions ◽  
Volume Variation ◽  
Capacity Decay

Transition metal oxide materials with high theoretical capacities have been studied as substitutes for commercial graphite in lithiumion batteries. Among these, SnO2 is a promising alloying reaction-based anode material. However, the problem of rapid capacity fading in SnO2 due to volume variation during the alloying/dealloying processes must be solved. The lithiation of SnO2 results in the formation of a Li2O matrix. Herein, the volume variation of SnO2 was suppressed by controlling the voltage window to 1 V to prevent the delithiation reaction between Li2O and Sn. Using this strategy the unreacted Li2O matrix was enriched with metallic Sn particles, thereby providing a pathway for lithium ions. The specific capacity decay in the voltage window of 0.05–3 V was 1.8% per cycle. However, the specific capacity decay was improved to 0.04% per cycle after the voltage window was restricted (in the range of 0.05–1 V). This strategy resulted in a specific capacity of 374.7 mAh g−1 at 0.1 C after 40 cycles for the SnO2 anode.

scholarly journals Efficacy of an 8-Week Concurrent Strength and Endurance Training program on Hand Cycling Performance

2018 ◽  
Vol 32 (7) ◽  
pp. 1861-1868 ◽  
Author(s):  
Jonpaul Nevin ◽  
Paul Smith ◽  
Mark Waldron ◽  
Stephen Patterson ◽  
Mike Price ◽  
...  
Keyword(s):  
Training Program ◽  
Endurance Training ◽  
Cycling Performance ◽  
Hand Cycling

The synthesis of ZnS@MoS2 hollow polyhedrons for enhanced lithium storage performance

CrystEngComm ◽  
2018 ◽  
Vol 20 (45) ◽  
pp. 7266-7274 ◽  
Author(s):  
Yueying Zhao ◽  
Wanwan Wang ◽  
Mengna Chen ◽  
Ruojie Wang ◽  
Zhen Fang
Keyword(s):  
Specific Capacity ◽  
Cycling Performance ◽  
Lithium Storage ◽  
Storage Performance

ZnS@MoS2 hollow polyhedrons display outstanding cycling performance and high reversible specific capacity in LIB anodes.

Hierarchical electrodes of NiCo2S4 nanosheets-anchored sulfur-doped Co3O4 nanoneedles with advanced performance for battery-supercapacitor hybrid devices

2019 ◽  
Vol 7 (7) ◽  
pp. 3228-3237 ◽  
Author(s):  
Yu Ouyang ◽  
Haitao Ye ◽  
Xifeng Xia ◽  
Xinyan Jiao ◽  
Guangmin Li ◽  
...  
Keyword(s):  
Specific Capacity ◽  
Cycling Performance ◽  
Sulfur Doping ◽  
Hybrid Devices

The specific capacity and cycling performance of the hierarchical electrode were significantly enhanced due to the sulfur doping into Co3O4.

scholarly journals Shape-Memory-Recovery Characteristics of Microcellular Foamed Thermoplastic Polyurethane

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 351
Author(s):  
Chang-Seok Yun ◽  
Joo Seong Sohn ◽  
Sung Woon Cha
Keyword(s):  
Shape Memory ◽  
Cell Density ◽  
Shape Recovery ◽  
Structural Changes ◽  
Thermoplastic Polyurethane ◽  
Testing Machine ◽  
Base Material ◽  
Memory Mechanism ◽  
Foaming Process ◽  
Dog Bone

We investigated the shape-recovery characteristics of thermoplastic polyurethane (TPU) with a microcellular foaming process (MCP). Additionally, we investigated the correlation between changes in the microstructure and the shape-recovery characteristics of the polymers. TPU was selected as the base material, and the shape-recovery characteristics were confirmed using a universal testing machine, by manufacturing dog-bone-type injection-molded specimens. TPUs are reticular polymers with both soft and hard segments. In this study, we investigated the shape-memory mechanism of foamed polymers by maximizing the shape-memory properties of these polymers through a physical foaming process. Toward this end, TPU specimens were prepared by varying the gas pressure, foaming temperature, and type of foaming gas in the batch MCP. The effects of internal structural changes were investigated. These experimental variables affected the microstructure and shape-recovery characteristics of the foamed polymer. The generated cell density changed, which affected the shape-recovery characteristics. In general, a higher cell density corresponded to a higher shape-recovery ratio.

Sulfur impregnation in polypyrrole-modified MnO2 nanotubes: efficient polysulfide adsorption for improved lithium–sulfur battery performance

Nanoscale ◽  
2019 ◽  
Vol 11 (20) ◽  
pp. 10097-10105 ◽  
Author(s):  
Pengcheng Du ◽  
Wenli Wei ◽  
Yuman Dong ◽  
Dong Liu ◽  
Qi Wang ◽  
...  
Keyword(s):  
Outer Layer ◽  
Specific Capacity ◽  
Cycling Performance ◽  
Lithium Sulfur Battery ◽  
Highly Efficient ◽  
Hollow Interior ◽  
Sulfur Host ◽  
Sulfur Battery ◽  
Lithium Sulfur

PPy-coated MnO2 nanotubes were fabricated as a highly efficient sulfur host. Hollow interior of the MnO2 nanotubes and the polypyrrole outer layer can effectively improve the specific capacity and maintain an extremely stable cycling performance.

scholarly journals Rechargeable Aqueous Zinc-Ion Batteries in MgSO4/ZnSO4 Hybrid Electrolytes

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Yingmeng Zhang ◽  
Henan Li ◽  
Shaozhuan Huang ◽  
Shuang Fan ◽  
Lingna Sun ◽  
...  
Keyword(s):  
Current Density ◽  
Specific Capacity ◽  
Cost Effective ◽  
Reversible Capacity ◽  
Zinc Ion ◽  
Rate Performance ◽  
Capacity Fading ◽  
Battery System ◽  
High Specific Capacity ◽  
A Current

AbstractMgSO4 is chosen as an additive to address the capacity fading issue in the rechargeable zinc-ion battery system of MgxV2O5·nH2O//ZnSO4//zinc. Electrolytes with different concentration ratios of ZnSO4 and MgSO4 are investigated. The batteries measured in the 1 M ZnSO4−1 M MgSO4 electrolyte outplay other competitors, which deliver a high specific capacity of 374 mAh g−1 at a current density of 100 mA g−1 and exhibit a competitive rate performance with the reversible capacity of 175 mAh g−1 at 5 A g−1. This study provides a promising route to improve the performance of vanadium-based cathodes for aqueous zinc-ion batteries with electrolyte optimization in cost-effective electrolytes.

Flower-like C@V2O5 microspheres as highly electrochemically active cathode in aqueous zinc-ion batteries

2020 ◽  
Vol 10 (10) ◽  
pp. 1697-1703
Author(s):  
Zebin Wu ◽  
Wei Zhou ◽  
Zhen Liu ◽  
Yijie Zhou ◽  
Guilin Zeng ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Retention Rate ◽  
Specific Capacity ◽  
Cycling Performance ◽  
Zinc Ion ◽  
Rate Performance ◽  
Capacity Retention ◽  
Facile Hydrothermal Method ◽  
High Specific Capacity ◽  
Electrochemically Active

Flower-like C@V2O5 microspheres with high specific capacity were synthesized by a facile hydrothermal method. The microstructure, specific capacity and electrochemical properties of C@V2O5 microspheres were studied. Results showed that the C@V2O5 microspheres with a diameter of ∼3 m are covered over by V2O5 nanosheets, and therefore have a large surface area which is almost 5 times higher than that of pure V2O5 powders. Moreover, the initial specific capacity of C@V2O5 microsphere is as high as 247.42 mAh · g–1, and after 100 cycles, the capacity retention rate is still 99.4%. Compared with pure V2O5, flower-like C@V2O5 microspheres show higher discharge specific capacity, better rate performance and more stable cycling performance.

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