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Al-0.05Ga-0.05Sn-0.05Pb-xMg alloys with different Mg content have been prepared. Electrochemical tests including constant current discharge test, current polarization test, electrochemical impedance spectroscopy (EIS) test, and Tafel test are performed. The surface states of the alloys after constant current discharge were analyzed by scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS). X-ray diffraction (XRD) analysis was carried out. We find that different Mg contents have great influence on discharge performance of aluminum alloy anodes by changing the corrosion behavior. The SEM and XRD show that Mg can influence the distribution of corrosion and change the grain size to improve the discharge performance of aluminum anodes. Al-0.05Ga-0.05Sn-0.05Pb-0.1Mg shows the best electrochemical performance due to uniform corrosion and proper grain size. At 800 mA cm−2 constant current discharge, the potential of the aluminum anode can reach − 1.54 V (vs Hg/HgO), and the utilization ratio is over 98%. [ABSTRACT FROM AUTHOR]

The all-solid-state lithium batteries using solid electrolytes are considered to be the new generation of devices for energy storage, which might be a key solution for power electric and hybrid electric vehicles in the future. This review focuses on the crystal structures and electrochemical properties of sulfide solid electrolytes. They are classified to several subgroups according to their chemical compositions, namely thiophosphates, halide thiophosphates, sulfide without phosphorus, and glassy sulfides electrolytes, which might be potential solid electrolytes in lithium batteries and may replace the currently used polymeric electrolytes for LIBs. Through discussion, this review provides an insight into future promising sulfide electrolytes. [ABSTRACT FROM AUTHOR]

In the past several years, many efforts have been made to develop polyanion-type cathode materials for sodium ion batteries by chemists and material scientists. These materials are one of the main types of promising cathodes though the studies are still in their infancy. This paper reviews almost all the important advances of polyanion-type cathodes on their syntheses, crystal structures, morphologies, electrochemical performance and Na redox mechanisms. It specifically focuses on their crystal chemistry and electrochemical behaviors. The contents are divided into several categories according to their chemical compositions. After introduction of the synthetic methods, phosphates (ortho-, pyro- and fluoro-), silicates, sulfates, and mixed anions type cathodes are summarized and discussed successively. [ABSTRACT FROM AUTHOR]

The γ-LiFeO micro-cubes were synthesized using a simple solid-state method. Their electrochemical performance as anode material for lithium ion batteries was firstly investigated. Pure γ-LiFeO without nanosizing or carbon coating can deliver the first discharge capacity of 1055.3 mAh/g, and 611.5 mAh/g can be maintained after 50 cycles, around 80 % of the second discharge capacity. γ-LiFeO also demonstrates nice rate capabilities. These results indicate that γ-LiFeO is a promising anode material candidate for lithium ion batteries. The charge/discharge mechanism was also investigated. [ABSTRACT FROM AUTHOR]

The FeSSe particles dispersed in the pores of carbon (FeSSe/PC) were prepared using a simple one-pot solid-state method, which were then characterized by XRD, SEM, TEM, XPS, and Raman spectrum techniques. As the anode material for lithium-ion batteries, FeSSe/PC displays an initial discharge capacity as high as 699.5 mAh/g at 0.1 C, and 327.9 mAh/g can be maintained after 200 cycles, much enhanced than those of pure FeSSe. The small particles of FeSSe wrapped in carbon can effectively buffer the volume expansion during charging/discharging to improve the electrochemical performance. [ABSTRACT FROM AUTHOR]

Recent years, there have been massive reports of layered double hydroxides (LDHs) used as electrode materials. However, the synergistic effect between different host metal ions on the electrochemical behavior of LDHs is rarely studied. We prepared a series of LDHs with different host metal combinations and investigated their physiochemical properties and redox behaviors to study the synergistic effects between different active metal ions. According to the experimental and theoretical calculation results, LDHs with dual transition metals possessed lower band-gap energies and higher conductivities than mono-transition metal-based samples. The reduced band-gap energy and enhanced conductivity should be ascribed to the hybridization between 3d-orbitals of different transition atoms. As a result, LDHs with dual transition metals exhibited lower charge transfer resistances and redox potentials as well as longer electron lifetime, implying that they could be oxidized or reduced more easily during the redox process. The lowest charge transfer resistance and longest electron lifetime of NiMn-LDHs signify that the synergistic effect between Ni and Mn is the best. From in situ X-ray photoelectron spectroscopy results, more than 50% Ni atoms in NiMn-LDHs can be oxidized under 0.45 V, which also demonstrates the excellent redox efficiency of NiMn-LDHs. [ABSTRACT FROM AUTHOR]

Abstract: The hierarchical carbon-coated LiFePO4 nano-grain microspheres are prepared by a chemical co-precipitation method. The microstructure and electrochemical properties of LiFePO4/C composites treated at 950–1025 K are intensively investigated. The rate discharge capability has been obviously enhanced when sample is treated at 1025 K. This attributes to its improved electric conductivity of 0.09 S cm−1 due to the in-situ formation of Fe2P phase. The cycling stabilities are excellent until 300 cycles for all the samples at the rate 1C in discharge, which is very difficult to reach for nano-grains with large specific surface area and high reaction activity. Our samples with hierarchical microstructures exhibit high Li-ion diffusion rate (10−9–10−13 cm2 S−1) with enhanced tap density (1.30 g cm−3). It is considered in our paper that the rate capacities increased by Li-ion diffusion rate are not as obvious as electric conductivity. Therefore, the LiFePO4/FePO4 reaction is a non-diffusional controlled process. [Copyright &y& Elsevier]

• NiCo-LDHs nanosheets featuring abundant Vo anchored on Ti 3 C 2 -MXene are synthesized. • The heterointerfaces between MXenes and Vo-LDHs show multifunctional synergistic effects. • The Vo-LDHs-MXenes cell delivers a high areal capacity under high sulfur loading and lean electrolyte. Lithium-sulfur batteries (LSBs) are increasingly seen as advanced battery systems of great promise, owing to their exceptional energy density and cost-effectiveness. Yet, designing efficient electrocatalysts that can both effectively mitigate the diffusion of soluble lithium polysulfides (LiPSs) and enhance redox kinetics still remains a significant challenge, particularly at high sulfur loadings and lean electrolyte conditions. In this work, we develop NiCo-layered double hydroxides (NiCo-LDHs) nanosheets featuring abundant oxygen vacancies (Vo), anchored on Ti 3 C 2 -MXene nanosheets (denoted as Vo-LDHs-MXenes), tailored specifically for high-performance LSBs. The heterointerfaces between MXenes and Vo-LDHs modify the electronic structure and enhance the catalytic activity of the LDHs and MXenes, yielding multifunctional synergistic effects. Our theoretical and electrochemical analyses indicate that the Vo-LDHs-MXenes heterostructures exhibit enhanced affinity for LiPSs and superior catalytic performances compared to individual LDHs. This improvement facilitates the efficient adsorption and conversion of LiPSs, as well as the nucleation and decomposition of Li 2 S. Consequently, the cell with the Vo-LDHs-MXenes modified separator delivers stable cycling performances with a high initial specific capacity of 938.9 mAh/g over 300cycles at 1.0C and good rate capabilities. Notably, it still achieves a high initial areal capacity of 6.09 mAh cm−2 under a high sulfur loading of 6.7 mg cm−2 and low electrolyte/sulfur (E/S) ratio of 6.0 μL mg−1 over 50cycles. [ABSTRACT FROM AUTHOR]

• CoSe nanoparticles embedded in N -doped carbon with in-situ growth of CNTs are synthesized. • Dual-mediators consist of heterogeneous (CoSe@CNTs) and homogeneous (CoCp 2) mediators. • Dual-mediation pathways improve sulfur redox kinetics under lean electrolyte. The high energy density (2500 Wh kg−1) makes that lithium–sulfur batteries (LSBs) have a great potential in energy storages. However, the practical application of LSBs is severely hampered by several inherent problems, including the sluggish sulfur redox kinetics, the shuttling of lithium polysulfides (LiPSs) and poor electronic conductivity. Although heterogeneous or homogeneous mediators could improve the cycling performance of LSBs to a certain extent, single mediators could not completely promote sulfur conversions, especially under high sulfur loading and lean electrolyte. Herein, dual-mediator systems consist of heterogeneous and homogeneous mediators that are introduced to address the above issues. Density functional theory (DFT) calculations and electrochemical analysis indicate that CoSe nanoparticles embedded in urchin-like nitrogen-doped porous carbon with in-situ growth of CNTs (CoSe@CNTs) as heterogeneous mediators and soluble CoCp 2 as homogeneous mediators could effectively accelerate the bidirectional conversion kinetics of liquid LiPSs ↔ solid Li 2 S through the synergistic effect. As a consequence, the cell with dual-mediators delivers a high initial specific capacity of 1005 mAh/g with a low attenuation rate of 0.045 % per cycle at a current density of 1.0C under sulfur loading of 2.8 mg cm−2 after 800cycles. Importantly, it still maintains a high areal capacity of 6.53 mAh cm−2 under lower electrolyte/sulfur ratio (E/S, 4.2 µL mg−1) and higher sulfur loading of 7.3 mg cm−2 over 100cycles at 0.1C. [ABSTRACT FROM AUTHOR]