Developing the next-generation high-energy density and safe batteries is of prime importance to meet the emerging demands in electronics, automobile industries and various energy storage systems. ...High-voltage lithium-ion batteries (LIBs) and solid-state batteries (SSBs) are two main directions attracting increasing interest in recent years, due to their potential applications in the near future. In both kinds of batteries, the electrolytes play a pivotal role but also create several bottleneck problems. In this review, recent progress in designing electrolytes for high-voltage LIBs and SSBs is summarized. First, the solvents, additives, ionic liquids and superconcentrated salts strategies for constructing high-voltage liquid electrolytes are reviewed, and then the applications of inorganic solids, solid polymers, gels and ionic liquids in solid-state electrolytes are presented. Finally, the general design rules of the electrolytes and their current limitations and future prospects are briefly discussed.
Graphene has attracted immense investigation since its discovery.Lattice imperfections are introduced into graphene unavoidably during graphene growth or processing.These structural defects are known ...to significantly affect electronic and chemical properties of graphene.A comprehensive understanding of graphene defect is thus of critical importance.Here we review the major progresses made in defectrelated engineering of graphene.Firstly,we give a brief introduction on the types of defects in graphene.Secondly,the generation and healing of the graphene defects are summarized.Then,the effects of defects on the chemical,electronic,magnetic,and mechanical properties of graphene are discussed.Finally,we address the associated challenges and prospects on the future study of defects in graphene and other nanocarbon materials.
In this work, a high‐voltage output and long‐lifespan zinc/vanadium oxide bronze battery using a Co0.247V2O5⋅0.944H2O nanobelt is developed. The high crystal architecture could enable fast and ...reversible Zn2+ intercalation/deintercalation at highly operational voltages. The developed battery exhibits a high voltage of 1.7 V and delivers a high capacity of 432 mAh g−1 at 0.1 A g−1. The capacity at voltages above 1.0 V reaches 227 mAh g−1, which is 52.54% of the total capacity and higher than the values of all previously reported Zn/vanadium oxide batteries. Further study reveals that, compared with the pristine vanadium oxide bronze, the absorption energy for Zn2+ increases from 1.85 to 2.24 eV by cobalt ion intercalation. Furthermore, it also shows a high rate capability (163 mAh g−1 even at 10 A g−1) and extraordinary lifespan over 7500 cycles, with a capacity retention of 90.26%. These performances far exceed those for all reported zinc/vanadium oxide bronze batteries. Subsequently, a nondrying and antifreezing tough flexible battery with a high energy density of 432 Wh kg−1 at 0.1 A g−1 is constructed, and it reveals excellent drying and freezing tolerance. This research represents a substantial advancement in vanadium materials for various battery applications, achieving both a high discharge voltage and high capacity.
Zn/vanadium oxide batteries can deliver a capacity greater than 300 mAh g−1, but their operational voltage is always very low. A 1.7 V high‐voltage Zn/vanadium battery is developed using a Co0.247V2O5 ⋅ 0.944H2O cathode. Its capacity at greater than 1.0 V reaches 227 mAh g−1, which is 52.54% of the total capacity and higher than the values of all previously reported Zn/vanadium oxide batteries.
LiNi
0.8
Co
0.1
Mn
0.1
O
2
(NCM811) has received widespread attention due to its high discharge specific capacity. However, poor cycling performance and rate capacity limit its large-scale commercial ...applications. Here, we develop 4,5-Dicyano-1,3-dithiol-2-one (DDO) as a new type additive to enhance the cycling performance and rate capacity of NCM811/Li
+
half cell. Electrochemical tests show that the discharge capacity retention rate of cell is 75.59% after 200 cycles with 0.1 wt% DDO-containing electrolyte, while the cell with blank electrolyte is only 15.11%. The initial coulomb efficiency and rate capacity with 0.1 wt% DDO are higher than the blank one. Through scanning electron microscope (SEM) analysis, the particle of NCM811 is smooth and integral after 50th cycled, while the particle ruptures in blank electrolyte. The outstanding electrochemical performance of NCM811 is attributed to the stable and uniform cathode electrolyte interphase (CEI) film formed by DDO. Moreover, X-ray photoelectron spectroscopy (XPS) reveals that DDO prevents the decomposition of carbonate solvents and nickel element dissolution of NCM811. Other tests also confirm that the robust CEI layer can reduce the polarization and internal resistance of the cell during cycles.
A new facile route to fabricate N‐doped graphene‐SnO2 sandwich papers is developed. The 7,7,8,8‐tetracyanoquinodimethane anion (TCNQ−) plays a key role for the formation of such structures as it acts ...as both the nitrogen source and complexing agent. If used in lithium‐ion batteries (LIBs), the material exhibits a large capacity, high rate capability, and excellent cycling stability. The superior electrochemical performance of this novel material is the result from its unique features: excellent electronic conductivity related to the sandwich structure, short transportation length for both lithium ions and electrons, and elastomeric space to accommodate volume changes upon Li insertion/extraction.
Superior electrochemical performance of lithium‐ion batteries is obtained using N‐doped graphene‐SnO2 sandwich papers. Using this novel material as the anode for lithium‐ion batteries results in a larger capacity, better high rate capability, and excellent cycling stability. These results can be attributed to the unique structure of the material.
The main challenge associated with sodium-ion battery (SIB) anodes is a search for novel candidate materials with high capacity and excellent rate capability. The most commonly used and effective ...route for graphene-based anode design is the introduction of in-plane "hole" defects via nitrogen-doping; this creates a spacious reservoir for storing more energy. Inspired by mountains in nature, herein, we propose another way - the introduction of blistering in graphene instead of making "holes"; this facilitates adsorbing/inserting more Na+ ions. In order to properly answer the key question: ""protrusions" or "holes" in graphene, which is better for sodium ion storage?", two types of anode materials with a similar doping level were designed: a phosphorus-doped graphene (GP, with protrusions) and a nitrogen-doped graphene (GN, with holes). As compared with GN, the GP anode perfectly satisfies all the desired criteria: it reveals an ultrahigh capacity (374 mA h g-1 after 120 cycles at 25 mA g-1) comparable to the best graphite anodes in a standard Li-ion battery ( similar to 372 mA h g-1), and exhibits an excellent rate capability (210 mA h g-1 at 500 mA g-1). In situ transmission electron microscopy (TEM) experiments and density functional theory (DFT) calculations were utilized to uncover the origin of the enhanced electrochemical activity of "protrusions" compared to "holes" in SIBs, down to the atomic scale. The introduction of protrusions through P-doping into graphene is envisaged to be a novel effective way to enhance the capacity and rate performance of SIBs.
In this communication, we report our finding on the transition of ionic liquid bmimPF6 from the liquid state to high-melting-point crystal when confined in multiwalled carbon nanotubes. This novel ...crystallization behavior is explained by the nanosized effect of carbon nanotubes on the structure of ionic liquid.
Hard-carbon is considered as one of the most promising anode materials for sodium-ion batteries (SIBs). Now it is imperative to develop a proper preparation method to obtain hard carbon anode ...particles with high initial coulombic efficiency and good cycling performance. In this paper, we have successfully prepared high performance hard carbon anodes, by selecting abundant and low-cost pinecones as biomass precursor and optimizing the preparation parameters of pinecone-derived hard carbon (PHC). The microstructure of PHC is studied by X-ray diffraction (XRD), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM) as well as nitrogen adsorption–desorption isotherm methods. The performance of PHC is highly dependent on the carbonization temperature. Increasing carbonization temperature of pinecone precursor can reduce surface area and thus improve the initial coulombic efficiency. Varying carbonization temperature can also adjust the slope and plateau capacity of PHC, and then regulate the energy density and power characteristics of PHC in battery operation. PHC1400 still delivers a capacity of 334 mA h g −1 after 120 cycles, with a high initial coulombic efficiency of 85.4%. Our results suggest that PHC is a promising anode material for practical large-scale SIB application.
Three different types of new electrolyte additives were adopted as flame retardant to improve the safety of nickel-cobalt-aluminum (LiNio.8Co0.15Al0.05O2,abbreviation NCA) based lithium batteries.By ...adding 5 wt％ of the additives,an obvious flame retardant effect can be observed for the electrolyte.Furthermore,it was found that the additives can help for forming a stable cathode electrolyte interface (CEI) film on the NCA cathode,which are important for enhancing the thermal stability of the electrolyte and make the electrolyte obviously reduce the flammability,as well as good effect on the cycling cycle performance of the battery.These results indicate that our flame retardant are favorable additives in conventional liquid electrolytes for rechargeable lithium-ion batteries with good safety and high performances.
Highly stable silver nanoparticles were successfully synthesized by gamma ray irradiation in the presence of sodium alginate. The silver nanoparticles were characterized by UV–vis spectroscopy, X-ray ...diffraction (XRD), and transmission electron microscopy (TEM). Their particle sizes were in the range of 6–30
nm. The as-obtained Ag nanoparticle dispersion was stable for over 6 months at room temperature.
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