High rate electrochemical performances of nanosized ZnO and carbon co-coated LiFePO4 cathode

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.

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High Capacity and Fast Kinetics of Potassium-Ion Batteries Boosted by Nitrogen-Doped Mesoporous Carbon Spheres

Nano-Micro Letters ◽

10.1007/s40820-021-00706-3 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Jiefeng Zheng ◽

Yuanji Wu ◽

Yong Tong ◽

Xi Liu ◽

Yingjuan Sun ◽

...

Keyword(s):

Mesoporous Carbon ◽

Active Sites ◽

Carbon Materials ◽

Potassium Ion ◽

High Rate ◽

Electrochemical Performances ◽

Carbon Spheres ◽

Fast Kinetics ◽

Nitrogen Doped ◽

Economic Price

AbstractIn view of rich potassium resources and their working potential, potassium-ion batteries (PIBs) are deemed as next generation rechargeable batteries. Owing to carbon materials with the preponderance of durability and economic price, they are widely employed in PIBs anode materials. Currently, porosity design and heteroatom doping as efficacious improvement strategies have been applied to the structural design of carbon materials to improve their electrochemical performances. Herein, nitrogen-doped mesoporous carbon spheres (MCS) are synthesized by a facile hard template method. The MCS demonstrate larger interlayer spacing in a short range, high specific surface area, abundant mesoporous structures and active sites, enhancing K-ion migration and diffusion. Furthermore, we screen out the pyrolysis temperature of 900 °C and the pore diameter of 7 nm as optimized conditions for MCS to improve performances. In detail, the optimized MCS-7-900 electrode achieves high rate capacity (107.9 mAh g−1 at 5000 mA g−1) and stably brings about 3600 cycles at 1000 mA g−1. According to electrochemical kinetic analysis, the capacitive-controlled effects play dominant roles in total storage mechanism. Additionally, the full-cell equipped MCS-7-900 as anode is successfully constructed to evaluate the practicality of MCS.

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Enhanced Electrochemical Hydrogen Storage Characteristics of the as-Spun Mg2Ni-Type Alloys by Substituting Ni with M (M=Cu, Co)

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.457-458.572 ◽

2012 ◽

Vol 457-458 ◽

pp. 572-577

Author(s):

Yang Huan Zhang ◽

Bao Wei Li ◽

Hui Ping Ren ◽

Zai Guang Pang ◽

Zhong Hui Hou ◽

...

Keyword(s):

Hydrogen Storage ◽

Melt Spinning ◽

Nanocrystalline Structure ◽

Amorphous Structure ◽

High Rate ◽

Electrochemical Performances ◽

Secondary Phases ◽

Nanocrystalline And Amorphous ◽

Electrochemical Hydrogen Storage ◽

Rate Discharge

Mg2Ni-type Mg20Ni10-xMx (M=Cu, Co; x=0, 1, 2, 3, 4) electrode alloys with nanocrystalline and amorphous structure were synthesized by melt-spinning technique. The microstructures of the as-spun alloys were characterized by XRD, SEM and HRTEM. The electrochemical hydrogen storage properties of the experimental alloys were measured. The obtained results show that the as-spun (M=Cu) alloys hold an entire nanocrystalline structure, whereas the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. Furthermore, such substitution results in the formation of secondary phases Mg2Cu and MgCo2 instead of changing the major phase of Mg2Ni. The substitution of M (M=Cu, Co) for Ni markedly improves the electrochemical performances of the alloys, involving the discharge capacity and the cycle stability as well as the high rate discharge ability.

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Modification of Li- and Mn-Rich Cathode Materials via Formation of the Rock-Salt and Spinel Surface Layers for Steady and High-Rate Electrochemical Performances

ACS Applied Materials & Interfaces ◽

10.1021/acsami.0c07497 ◽

2020 ◽

Vol 12 (29) ◽

pp. 32698-32711

Author(s):

Sandipan Maiti ◽

Hadar Sclar ◽

Rosy ◽

Judith Grinblat ◽

Michael Talianker ◽

...

Keyword(s):

Rock Salt ◽

Cathode Materials ◽

High Rate ◽

Electrochemical Performances ◽

Surface Layers

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Stable Copper Tin Sulfide Nanoflower Modified Carbon Quantum Dots for Improved Supercapacitors

Journal of Chemistry ◽

10.1155/2019/6109758 ◽

2019 ◽

Vol 2019 ◽

pp. 1-5 ◽

Cited By ~ 1

Author(s):

Zhen Bi ◽

Lanyan Huang ◽

Chaoqun Shang ◽

Xin Wang ◽

Guofu Zhou

Keyword(s):

Quantum Dots ◽

Volume Change ◽

Electrode Materials ◽

Rate Capability ◽

Carbon Quantum Dots ◽

High Rate ◽

Electrochemical Performances ◽

Tin Sulfide ◽

Transmission Electron ◽

Tin Sulfides

Copper tin sulfides (CTSs) have widely been investigated as electrode materials for supercapacitors owing to their high theoretical pseudocapacitances. However, the poor intrinsic conductivity and volume change during redox reactions hindered their electrochemical performances and broad applications. In this study, carbon quantum dots (CQDs) were employed to modify CTSs. The structures and morphologies of obtained materials were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD revealed CTSs were composed of Cu2SnS3 and Cu4SnS4, and TEM suggested the decoration of CQDs on the surface of CTSs. With the decoration of CQDs, CTSs@CQDs showed a remarkable specific capacitance of 856 F·g−1 at 2 mV·s−1 and a high rate capability of 474 F·g−1 at 50 mV·s−1, which were superior to those of CTSs (851 F·g−1 at 2 mV·s−1 and 192 F·g−1 at 50 mV·s−1, respectively). This was mainly ascribed to incorporation of carbon quantum dots, which improved the electrical conductivity and alleviated volume change of CTSs during charge/discharge processes.

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Enhanced Electrochemical Hydrogen Storage Characteristics of Mg2Ni-Type Alloy by Substituting Mg with La

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.399-401.1461 ◽

2011 ◽

Vol 399-401 ◽

pp. 1461-1466

Author(s):

Hui Ping Ren ◽

Bao Wei Li ◽

Yin Zhang ◽

Zai Guang Pang ◽

Zhong Hui Hou ◽

...

Keyword(s):

Melt Spinning ◽

Amorphous Structure ◽

High Rate ◽

Electrochemical Performances ◽

Type Alloy ◽

Major Phase ◽

Nanocrystalline And Amorphous ◽

Ni Alloy ◽

Electrochemical Hydrogen Storage ◽

Cast Alloys

The melt-spinning technique is applied to the preparation of the nanocrystalline and amorphous Mg2Ni-type alloys with nominal compositions of Mg2-xLaxNi (x=0, 0.2, 0.4, 0.6). The as-spun alloy ribbons possessing a continuous length, a thickness of about 30 μm and a width of about 25 mm were prepared. The structures of the as-spun alloy ribbons are characterized by XRD, SEM and TEM. The electrochemical performances of the as-spun alloy ribbons are measured by an automatic galvanostatic system. The results show that no amorphous structure is detected in the as-spun Mg2Ni alloy, whereas the as-spun alloys substituted by La display a nanocrystalline and amorphous structure, confirming that the substitution of La for Mg notably intensifies the amorphous forming ability of the Mg2Ni-type alloy. For La content x≤0.2, the substitution of La for Mg brings to the formation of LaMg3 and La2Mg17 phases without changing the Mg2Ni major phase. But as La content is increased to x≥0.4, such substitution changes the major phase of the alloys to (La, Mg)Ni3+LaMg3. The discharge capacity of the as-cast alloys grows with the increasing amount of La substitution, whereas that of the as-spun alloys yields a maximum value with variation of La content. Furthermore, the substitution of La for Mg remarkably enhances the cycle stability of the as-cast and spun alloys. And the high rate dischargeability (HRD) of the as-cast and spun alloys first mounts up then falls with rising La content.

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Polymer Modified MWCNT as Conductive Additive in LiFePO4 Cathode with High Rate Capability

ECS Meeting Abstracts ◽

10.1149/ma2011-02/17/1371 ◽

2011 ◽

Keyword(s):

Rate Capability ◽

High Rate ◽

High Rate Capability ◽

Conductive Additive ◽

Lifepo4 Cathode

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High-Rate and Long-Life Cycle of Nano-LiMn2O4 Under High Cut-Off Potential

Journal of Electrochemical Energy Conversion and Storage ◽

10.1115/1.4049317 ◽

2020 ◽

pp. 1-18

Author(s):

Zulhadi Radzi ◽

B Vengadaesvaran ◽

Nasrudin Abd Rahim ◽

Adarsh Kumar Pandey ◽

Khairul Helmy Arifin ◽

...

Keyword(s):

Lattice Strain ◽

Organic Reagent ◽

High Rate ◽

Electrochemical Performances ◽

Hydrothermal Route ◽

Capacity Retention ◽

Nanostructured Particles ◽

Pure Phase ◽

Small Lattice ◽

Spinel Structures

Abstract Nano-LiMn2O4 was successfully synthesized by a low-temperature hydrothermal route with the absence of post-calcination treatment. Employing ethanol as an organic reagent triggers the formation of nanostructured particles approximately 30.39 nm in diameter, associated with 0.7 % lattice strain. The pure phase of nano-LiMn2O4/Li displays outstanding electrochemical performances. Under 4.6 V vs Li+/Li cut-off potential, 74.3 % of capacity is reserved when C-rate is increased by 50 times, while excellent capacity restoration of 96.9 % after cycled again at 1 C. After 331 cycles, capacity retention of 84.3 % is harvested by nano-LiMn2O4/Li, implying the absence of phase transformations in spinel structures under such abuse condition. This remarkable structural stability can be attributed to the small lattice strain, associated with high Li+ diffusion coefficient, which is estimated to be 10-9.76 cm2 s-1 by the EIS technique. Additionally, Li+ extraction is more favourable when nano-LiMn2O4/Li is charged up to 4.6 V vs Li+/Li, interpreted by the polarization resistance (Rp) of the cell.

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