High Energy Hybrid Capacitor with Quinone-Grafted Negative Electrode in Neutral Aqueous Electrolyte

2016 ◽  
Keyword(s):  
Aqueous Electrolyte ◽  
Negative Electrode ◽  
High Energy ◽  
Neutral Aqueous Electrolyte

scholarly journals Nanosized and metastable molybdenum oxides as negative electrode materials for durable high-energy aqueous Li-ion batteries

2021 ◽  
Vol 118 (48) ◽  
pp. e2024969118
Author(s):  
Jeongsik Yun ◽  
Ryota Sagehashi ◽  
Yoshihiko Sato ◽  
Takuya Masuda ◽  
Satoshi Hoshino ◽  
...  
Keyword(s):  
Energy Density ◽  
Electrode Material ◽  
Electrode Materials ◽  
Aqueous Electrolyte ◽  
Negative Electrode ◽  
High Energy ◽  
Li Ion Batteries ◽  
Li Ion ◽  
Negative Electrode Material ◽  
Negative Electrode Materials

The development of inherently safe energy devices is a key challenge, and aqueous Li-ion batteries draw large attention for this purpose. Due to the narrow electrochemical stable potential window of aqueous electrolytes, the energy density and the selection of negative electrode materials are significantly limited. For achieving durable and high-energy aqueous Li-ion batteries, the development of negative electrode materials exhibiting a large capacity and low potential without triggering decomposition of water is crucial. Herein, a type of a negative electrode material (i.e., LixNb2/7Mo3/7O2) is proposed for high-energy aqueous Li-ion batteries. LixNb2/7Mo3/7O2 delivers a large capacity of ∼170 mA ⋅ h ⋅ g−1 with a low operating potential range of 1.9 to 2.8 versus Li/Li+ in 21 m lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) aqueous electrolyte. A full cell consisting of Li1.05Mn1.95O4/Li9/7Nb2/7Mo3/7O2 presents high energy density of 107 W ⋅ h ⋅ kg−1 as the maximum value in 21 m LiTFSA aqueous electrolyte, and 73% in capacity retention is achieved after 2,000 cycles. Furthermore, hard X-ray photoelectron spectroscopy study reveals that a protective surface layer is formed at the surface of the negative electrode, by which the high-energy and durable aqueous batteries are realized with LixNb2/7Mo3/7O2. This work combines a high capacity with a safe negative electrode material through delivering the Mo-based oxide with unique nanosized and metastable characters.

scholarly journals High-Energy Density Asymmetric Supercapacitor Based on Electrospun Vanadium Pentoxide and Polyaniline Nanofibers in Aqueous Electrolyte

2012 ◽  
Vol 159 (9) ◽  
pp. A1481-A1488 ◽  
Author(s):  
Wai Fatt Mak ◽  
Grace Wee ◽  
Vanchiappan Aravindan ◽  
Nutan Gupta ◽  
Subodh G. Mhaisalkar ◽  
...  
Keyword(s):  
Energy Density ◽  
Vanadium Pentoxide ◽  
Aqueous Electrolyte ◽  
High Energy ◽  
High Energy Density ◽  
Asymmetric Supercapacitor ◽  
Polyaniline Nanofibers

scholarly journals Stable Lithium-Carbon Composite Enabled by Dual-Salt Additives

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Lei Zheng ◽  
Feng Guo ◽  
Tuo Kang ◽  
Yingzhu Fan ◽  
Wei Gu ◽  
...  
Keyword(s):  
Coulombic Efficiency ◽  
Solid Electrolyte Interphase ◽  
Rate Capability ◽  
Negative Electrode ◽  
High Energy ◽  
Carbon Composite ◽  
High Reactivity ◽  
Cycling Stability ◽  
High Energy Density ◽  
Lithium Metal

AbstractLithium metal is regarded as the ultimate negative electrode material for secondary batteries due to its high energy density. However, it suffers from poor cycling stability because of its high reactivity with liquid electrolytes. Therefore, continuous efforts have been put into improving the cycling Coulombic efficiency (CE) to extend the lifespan of the lithium metal negative electrode. Herein, we report that using dual-salt additives of LiPF6 and LiNO3 in an ether solvent-based electrolyte can significantly improve the cycling stability and rate capability of a Li-carbon (Li-CNT) composite. As a result, an average cycling CE as high as 99.30% was obtained for the Li-CNT at a current density of 2.5 mA cm–2 and an negative electrode to positive electrode capacity (N/P) ratio of 2. The cycling stability and rate capability enhancement of the Li-CNT negative electrode could be attributed to the formation of a better solid electrolyte interphase layer that contains both inorganic components and organic polyether. The former component mainly originates from the decomposition of the LiNO3 additive, while the latter comes from the LiPF6-induced ring-opening polymerization of the ether solvent. This novel surface chemistry significantly improves the CE of Li negative electrode, revealing its importance for the practical application of lithium metal batteries.

Hierarchical coral-like MnCo2O4.5@Co-Ni LDH composites on Ni foam as promising electrodes for high-performance supercapacitor

2021 ◽  
Author(s):  
yajun JI ◽  
Fei Chen ◽  
Shufen Tan ◽  
Fuyong Ren
Keyword(s):  
Electrochemical Performance ◽  
Metal Oxides ◽  
High Performance ◽  
High Capacity ◽  
Rate Capability ◽  
Negative Electrode ◽  
High Energy ◽  
Hybrid Nanostructures ◽  
High Energy Density ◽  
Ni Foam

Abstract Transition metal oxides are generally designed as hybrid nanostructures with high performance for supercapacitors by enjoying the advantages of various electroactive materials. In this paper, a convenient and efficient route had been proposed to prepare hierarchical coral-like MnCo2O4.5@Co-Ni LDH composites on Ni foam, in which MnCo2O4.5 nanowires were enlaced with ultrathin Co-Ni layered double hydroxides nanosheets to achieve high capacity electrodes for supercapacitors. Due to the synergistic effect of shell Co-Ni LDH and core MnCo2O4.5, the outstanding electrochemical performance in three-electrode configuration was triggered (high area capacitance of 5.08 F/cm2 at 3 mA/cm2 and excellent rate capability of maintaining 61.69 % at 20 mA/cm2), which is superior to those of MnCo2O4.5, Co-Ni LDH and other metal oxides based composites reported. Meanwhile, the as-prepared hierarchical MnCo2O4.5@Co-Ni LDH electrode delivered improved electrical conductivity than that of pristine MnCo2O4.5. Furthermore, the as-constructed asymmetric supercapacitor using MnCo2O4.5@Co-Ni LDH as positive and activated carbon as negative electrode presented a rather high energy density of 220 μWh/cm2 at 2400 μW/cm2 and extraordinary cycling durability with the 100.0 % capacitance retention over 8000 cycles at 20 mA/cm2, demonstrating the best electrochemical performance compared to other asymmetric supercapacitors using metal oxides based composites as positive electrode material. It can be expected that the obtained MnCo2O4.5@Co-Ni LDH could be used as the high performance and cost-effective electrode in supercapacitors.

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