Surface-roughened current collectors for anode-free all-solid-state batteries

Anode-free all-solid-state batteries(AFASSBs), composed of a fully lithiated cathode and a bare current collector(CC) that eliminates excess lithium, can maximize the energy density(because of a compact cell configuration) and improve the safety of solid-state systems. Although significant progress has been made by modifying CCs in liquid-based anode-free batteries, the role of CCs and the mechanism of Li formation on CCs in AFASSBs are still unexplored. Here, we systematically investigate the e...     

How the electrolyte limits fast discharge in nanostructured batteries and supercapacitors

Solid state and interfacial processes are not necessarily the principal rate limiting process during fast discharge of LiFePO₄ composite electrodes with particle size less than 1 μm. A simple model based on salt diffusion to a sharp discharge front explains the observed dependence of discharge rate on electrode thickness, electrolyte concentration, lithium transference number, and dilution of the active material. The effect of changing the electrolyte is dramatic, e.g. discharge to 25% capacity was obtained on a 40 μm thick electrode after only 4 s in an optimised electrolyte, aqueous Li₂SO₄, showing a rate of 900 C as compared with less than 10 C for a similar cell with an ionic liquid as the electrolyte.     

Predicting autoxidation stability of ether- and amide-based electrolyte solvents for Li-air batteries

Finding suitable solvents remains one of the most elusive challenges in rechargeable, nonaqueous Li-air battery technology. Although ether and amides are identified as stable classes of aprotic solvents against nucleophilic attack by superoxide, many of them are prone to autoxidation under oxygen atmosphere. In this work, we use density functional theory calculations coupled with an implicit solvent model to investigate the autoxidative stability of ether- and N,N-dialkylamide-based solvents. The change in the activation free energy for the C-H bond cleavage by O(2) is consistent with the extent of peroxide production for each class of solvent. Conversely, the thermodynamic stability alone is not sufficient to account for the observed variation in solvent reactivity toward O(2). A detailed understanding of the factors influencing the autoxidative stability provides several strategies for designing molecules with enhanced air/O(2) stability, comparable or superior to that of structurally related hydrocarbons. The mechanism of superoxide-mediated oxidation of hydroperoxides derived from ethers and amides is presented. The degradation mechanism accounts for the primary decomposition products (esters and carboxylates) observed in the Li-air battery with ether-based electrolytes. The identification of solvents having resistance to autoxidation is critical for the development of rechargeable Li-air batteries with long cycle life.     

Electrochemical characterization of non-stoichiometric Cu2S x cathode for lithium batteries

Journal of Solid State Electrochemistry - Electrochemical performances of non-stoichiometric Cu2S x (1.25 ≤ x ≤ 0.625) cathodes prepared by spray...     

Electrochemical performance of catalyst couples M/stainless steel 430 (M: Ni,Co, and Cu) for the hydrogen production in KOH electrolyte

Journal of Solid State Electrochemistry - In this work, three catalysts (nickel, cobalt, copper) are electrochemically deposited on stainless steel substrates AISI 430 and their performances as...     

Ultralow-strain Ti substituted Mn-vacancy layered oxides with enhanced stability for sodium-ion batteries

Anionic redox reaction (ARR) in layered manganese-based oxide cathodes has been considered as an effective strategy to improve the energy density of sodium-ion ...     

Effect of carbon foams as negative current collectors on partial-state-of-charge performance of lead acid batteries

Flooded lead acid batteries were assembled by using a pitch-based carbon foam and a punched lead sheet as the negative current collectors, respectively. Comparative galvanostatic charge–discharge experiments were performed on the batteries to evaluate the effect of the carbon foam as a negative current collector material on the performance of lead acid batteries under partial-state-of-charge operation. The results indicate that the carbon foam negative current collector can significantly improve the cyclability of lead acid batteries under partial-state-of-charge operation. This is mainly attributed to the high specific surface area and three-dimensional, interconnected carbon ligaments of the carbon foam negative current collector.     

Electrochemical performance of sol-gel-made Na2Ti3O7 anode material for Na-ion batteries

Journal of Solid State Electrochemistry - Nanocrystalline Na2Ti3O7 material is prepared by a newly developed sol-gel procedure. The sol-gel made Na2Ti3O7 calcined at 500 °C possesses...     

Electrochemical properties and stability of emulsifier-free polystyrene latexes in 1: 1 electrolyte solutions

The electrokinetic and adsorption characteristics of monodisperse emulsifier-free latexes of polystyrene (particle sizes of 0.25–0.40 μm) with surface carboxyl and sulfo groups are comprehensively studied depending on pH and the concentration of background NaCl solutions. The constants of surface carboxyl group dissociation and surface complexation, as well as the adsorption potentials of OH^? and Na⁺ ions, are calculated. The stability of latex suspensions is investigated and the coagulating concentrations of NaCl and HCl solutions are determined. An analysis of the curves plotted for the pair interaction between latex particles at different concentrations of NaCl solutions suggests that the system possesses an additional stability factor, which is probably associated with polymer chains that protrude over the particle surface into a solution.     

Asymmetric double-layer composite electrolyte with enhanced ionic conductivity and interface stability for all-solid-state lithium metal batteries

All-solid-state Li metal battery has been regarded as a promising battery technology due to its high energy density based on the high capacity of lithium metal anode and high safety based on the all solid state electrolyte without inflammable solvent.However,challenges still exist mainly in the poor contact and unstable interface between electrolyte and electrodes.Herein,we demonstrate an asymmetric design of the composite polymer electrolyte with two different layers to overcome the interface issues at both the cathode and the anode side simultaneously.At the cathode side,the polypropylene carbonate layer has enough viscosity and flexibility to reduce the inter-facial resistance,while at the Li anode side,the polyethylene oxide layer modified with hexagonal boron nitride has high mechanical strength to suppress the Li dendrite growth.Owing to the synergetic effect between different components,the asprepared double layer composite polymer electrolyte demonstrates a large electrochemical window of5.17 V,a high ionic conductivity of 6.1×10~(-4) S/cm,and a transfe rence number of 0.56,featuring excellent ion transport kinetics and good chemical stability.All-solid-state Li metal battery assembled with LiFePO_4 cathode and Li anode delivers a high capacity of 150.9 mAh/g at 25℃ and 0.1 C-rate,showing great potential for practical applications.     

Electrochemical and in-situ X-ray diffraction studies of Ti3C2Tx MXene in ionic liquid electrolyte

2D titanium carbide (Ti₃C₂T_x MXene) showed good capacitance in both organic and neat ionic liquid electrolytes, but its charge storage mechanism is still not fully understood. Here, electrochemical characteristics of Ti₃C₂T_x electrode were studied in neat EMI-TFSI electrolyte. A capacitive behavior was observed within a large electrochemical potential range (from − 1.5 to 1.5 V vs. Ag). Intercalation and de-intercalation of EMI⁺ cations and/or TFSI⁻ anions were investigated by in-situ X-ray diffraction. Interlayer spacing of Ti₃C₂T_x flakes decreases during positive polarization, which can be ascribed to either electrostatic attraction effect between intercalated TFSI⁻ anions and positively charged Ti₃C₂T_x nanosheets or steric effect caused by de-intercalation of EMI⁺ cations. The expansion of interlayer spacing when polarized to negative potentials is explained by steric effect of cation intercalation.     

Electrochemical performance of all solid-state fluoride-ion batteries based on thin-film electrolyte using alternative conductive additives and anodes

Journal of Solid State Electrochemistry - CaF2 and MgF2 were tested as active anode materials for solid-state fluoride-ion battery based on thin-film electrolyte. Tin oxide, indium tin oxide, and...     

铝-空气电池电解液的研究现状

综述了铝-空气电池电解液及其添加剂的研究与发展现状,重点分析讨论了影响电解液性能的主要因素以及无机离子、有机物和复合物等添加剂在铝．空气电池中的作用、机理、应用。说明了Ga^3 ,In^3 ,配位剂,复合物是最有希望成为一种实际应用于铝．空气电池的添加剂。     

Electrochemical performances of a new solid composite polymer electrolyte based on hyperbranched star polymer and ionic liquid for lithium-ion batteries

Journal of Solid State Electrochemistry - A new composite polymer electrolyte membrane composed of hyperbranched star polymers (HBPS-(PMMA-b-PPEGMA)30 (the hyperbranched star polymer with...     

Enhanced efficiency and stability of 3.3 V Cu-Li batteries by tuning the cation-anion interaction in the electrolyte

Cu-Li battery with Cu metal cathode and Li metal anode is a candidate for next-generation energy storage system. While self-discharge of the battery can be suppressed with an anion exchange membrane, the voltage polarization depends strongly on the electrolyte. Specifically, when an electrolyte with 3 M LiTFSI(lithium bis(trifluoromethanesulfonyl)imide) in dimethyl carbonate(DMC) is used, overpotential increases with cycling. In this work, we reveal why the voltage polarization changes, and redu...     

Nickel metal-organic framework nanoparticles as electrode materials for Li-ion batteries and supercapacitors

Journal of Solid State Electrochemistry - Nickel-based metal-organic framework ([Ni(4,4′-bpy)(tfbdc)(H2O)2], Ni-MOF) nanoparticles with the size of 45–250 nm were synthesized...     

锂离子电池有机电解液材料研究进展

综述了锂离子电池有机电解液材料的研究现状。锂离子电池有机电解液主要由电解质锂盐、有机溶剂和添加剂三个部分组成,新型电解质锂盐的研究开发可分为三个方面：（1）LiTFSI及其类似物;（2）络合硼酸锂化合物;（3）络合磷酸锂化合物。有机溶剂的研究工作主要集中在新型有机溶剂的开发上。最重要的添加剂主要有三类：（1）主要用以改善碳负极SEI膜性能的添加剂;（2）过充电保护添加剂;（3）配体添加剂。     

A measurement method for determination of dc internal resistance of batteries and supercapacitors

Internal resistance is an importance parameter determining the power performance of a battery or supercapacitor. An 8.5 Ah Li-ion battery and a 350 F supercapacitor were tested as examples to validate the measurement method of dc internal resistance. Voltage data were taken at 10 ms, 2 s and 30 s after the current interruption or pulse. The ac resistances at 1 kHz of the battery and supercapacitor were also measured for comparison with the dc values. Based on these tests, it is proposed that the dc internal resistance of the battery and supercapacitor be obtained from ΔV/ΔI where the ΔV is the voltage change after the current interruption, and ΔI means current change from I to 0. When the voltage change at 10 ms or less is selected, the resistance corresponds to the Ohmic resistance of the device.     

Synthesis of Co3O4/CoOOH via electrochemical dispersion using a pulse alternating current method for lithium-ion batteries and supercapacitors

We report a convenient, low-cost and ecofriendly approach for the fabrication of a Co₃O₄/CoOOH electrode material intended for lithium ion batteries (LIBs) and supercapacitors (SCs) using the electrochemical dispersion of the cobalt foil through the pulse alternating current (PAC) method. The synthesized material is a Co₃O₄/CoOOH composite (with about 10–15 wt% CoOOH) in the form of nanosheets with a length of approximately 200 nm and a thickness of 10–20 nm. It is found to exhibit high reversible discharge specific capacities and good cycling behavior while tested as the anode material in LIBs. Measuring the reversible capacitance at high (2C) and low (C/20) cycling rates gives the values of 610 mAh g⁻¹ and 1030 mAh g⁻¹, respectively. The specimen possesses excellent performance as the electrode for SCs with the retention of capacitance up to 98% at the current density increasing from 0.5 to 10 A g⁻¹. After 1000 cycles at a current density of 10 A g⁻¹ the electrode maintains about 90% of its initial capacitance which evidences the long cycle life. Hence, electrochemically prepared Co₃O₄/CoOOH seems to be a promising candidate for high-performance LIBs and SCs applications.     

Enhancing interfacial stability in solid-state lithium batteries with polymer/garnet solid electrolyte and composite cathode framework

The solid-state lithium battery is considered as an ideal next-generation energy storage device owing to its high safety,high energy density and low cost.However,the poor ionic conductivity of solid electrolyte and low interfacial stability has hindered the application of solid-state lithium battery.Here,a flexible polymer/garnet solid electrolyte is prepared with poly(ethylene oxide),poly(vinylidene fluoride),Li6.75La3 Zr1.75Ta0.25O12,lithium bis(trifluoromethanesulfonyl)imide and oxalate,which exhibits an ionic conductivity of 2.0 ×10^-4 S cm^-1 at 55℃,improved mechanical property,wide electrochemical window(4.8 V vs.Li/Li+),enhanced thermal stabilities.Tiny acidic OX was introduced to inhibit the alkalinity reactions between Li6.75La3 Zr1.75Ta0.25O12 and poly(vinylidene fluoride).In order to improve the interfacial stability between cathode and electrolyte,an Al2 O3@LiNi0.5Co0.2Mn0.3O2 based composite cathode framework is also fabricated with poly(ethylene oxide) polymer and lithium salt as additives.The solid-state lithium battery assembled with polymer/garnet solid electrolyte and composite cathode framework demonstrates a high initial discharge capacity of 150.6 mAh g^-1 and good capacity retention of 86.7% after 80 cycles at 0.2 C and 55℃,which provides a promising choice for achieving the stable electrode/electrolyte interfacial contact in solid-state lithium batteries.