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Rechargeable aqueous Zn-ion battery has been considered as a key complement to the existing battery technologies due to its intrinsic merits such as operational safety and cost saving. However, issues of dendrite growth and accompanied water consumption hinder its further development. In this work, we utilize a chelating agent, 2-Bis(2-hydroxyethyl) amino-2-(hydroxymethyl)-1,3-propanediol (BIS-TRIS), to regulate the solvation sheath structure of Zn2+. Benefiting from such zinc-chelating coordination, Zn2+ 2D diffusion can be restricted and the altered deposition kinetic has contributed to the inhibition of the dendrite growth. In addition, partial substitution of water in solvation shell with chelator can also greatly suppress the competitive hydrogen evolution reaction (HER). Consequently, a stable symmetric Zn cell with lifetime more than 1000 h at a current density of 1 mA cm−2 is achieved. Moreover, the aqueous Zn/MnO2 battery with BIS-TRIS as electrolyte additive delivers an 86% capacity retention after 600 cycles at 500 mA g−1. This zinc-chelating coordination based facile strategy opens a new window for the future development in dendrite-free Zn anode.

In this work, garnet-framework Li3Nd3W2O12 as a novel insertion-type anode material has been prepared via a facile sol–gel method and examined as a lithium container for lithium ion batteries (LIBs...

The preparation and characterization of Pb1-xBaxLi2Ti6O14 (x = 0, 1/4, 1/2, 3/4, 1) as anode materials for lithium ion batteries are investigated in this research. The structure, morphology and electrochemical properties are compared with each other by changing the Pb/Ba atomic ratio in Pb1-xBaxLi2Ti6O14. It can be observed that each sample shows the same orthorhombic structure with Cmca space group. Moreover, it can also be found that the working potential, conductivity, cycling and rate performances of as-received samples gradually change along with the evolution of x in Pb1-xBaxLi2Ti6O14 (x = 0, 1/4, 1/2, 3/4, 1). Electrochemical evaluation shows that the operating potential of the as-received sample gradually decreases with increasing x value in Pb1-xBaxLi2Ti6O14 and its initial charge capacity increases reversely. Moreover, different Pb/Ba atomic ratio also brings different cycling stability for Pb1-xBaxLi2Ti6O14. Especially for Pb3/4Ba1/4Li2Ti6O14, it presents better electrochemical properties than other samples. After 120 cycles, the reversible capacity of Pb3/4Ba1/4Li2Ti6O14 is maintained at 129.7 mAh g−1 with capacity retention of 88.3%. In addition, its electrochemical reversibility is also demonstrated by in-situ X-ray investigation.

Isostructural LiMTiO 4 (M = Mn, Fe, Co) have been successfully synthesized by a facile sol-gel route and evaluated their possibility as an anode materials for lithium ion batteries (LIBs). All the samples exhibit high operating potential plateaus (>1.7 V vs. Li + /Li), which can prevent the formation of the solid electrolyte interphase (SEI) film on the electrode surface effectively. In addition, electrochemical investigations show that LiCoTiO 4 has a superior cycling performance, better rate capability, lower charge transfer resistance and higher lithium-ion diffusion coefficient than those of LiMnTiO 4 and LiFeTiO 4 . These electrochemical results indicate that LiCoTiO 4 is the most promising lithium storage material among all the examined spinel-type LiMTiO 4 samples.

Metal doping is an effective way to improve the electrochemical properties of titanates. In this work, Ba-site substituted Ba 0.9 M 0.1 Li 2 Ti 6 O 14 (M = K, Zn, La) are synthesized to fabricate high performance titanate anode for lithium-ion batteries. Electrochemical evaluations reveal that introducing metal doping at Ba-site can result in higher ionic/electronic conductivity. As a result, Ba 0.9 M 0.1 Li 2 Ti 6 O 14 exhibits enhanced lithium storage capability. Especially for Ba 0.9 La 0.1 Li 2 Ti 6 O 14 , it shows the best electrochemical performance with a high reversible charge capacity of 151.3 mAh g −1 and high capacity retention of 94.21% at a current density of 100 mA g −1 . For comparison, the pristine BaLi 2 Ti 6 O 14 only exhibits a reversible charge capacity of 128.5 mAh g −1 with the capacity retention of 80.06% after 100 cycles. Further, the lithium storage process is investigated in detail by in-situ structural observation, which reveals a maximum volume expansion of 1.9% for Ba 0.9 La 0.1 Li 2 Ti 6 O 14 during charge-discharge cycle. It shows that Ba 0.9 La 0.1 Li 2 Ti 6 O 14 is a possible material with high structural reversibility for lithium storage.

In order to investigate the lithiation-delithiation kinetics in BaLi2Ti6O14 anode material, BaLi2Ti6O14 is achieved by a solid-state reaction process in this work. The as-prepared BaLi2Ti6O14 is high purity titanate and well crystallized with a particle size distribution in the range of 0.5–1.5 μm. Electrochemical analysis shows that BaLi2Ti6O14 can deliver a reversible capacity of 126.1 mAh g− 1 at 5C, and the capacity retention is 74.1% after 1000 cycles. In addition, the electrochemical kinetics of BaLi2Ti6O14 is investigated by cyclic voltammetry (CV), in-situ electrochemical impedance spectroscopy (in-situ EIS) and galvanostatic intermittent titration (GITT) techniques. The DLi + values calculated from CVs are located in the range of 10− 13–10− 12 cm2 s− 1. For comparison, the average DLi + values received from EIS and GITT methods are located in the range of 10− 14–10− 12 cm2 s− 1 and 10− 14–10− 11 cm2 s− 1, respectively. Although the DLi + differs by several orders of magnitude from different measurement techniques, it still reveals higher value than that of Li4Ti5O12. Owing to the rapid diffusion kinetics of BaLi2Ti6O14, symmetrical structural evolutions can be observed via in-situ X-ray diffraction (XRD) study, which indicates that BaLi2Ti6O14 is a promising high-power anode candidate.

Spinel LiCrTiO4 is synthesized via sol-gel pretreatment and subsequent solid state reaction at different calcining temperatures. Structural observation and electrochemical evaluation show that 800 °C is a suitable calcining temperature for LiCrTiO4 preparation. Compared with samples prepared at other temperatures, LiCrTiO4 formed at 800 °C exhibits better electrochemical performance with the capacity retention of 92.2% at 100 mA g−1 after 80 cycles. Even cycled at a higher current density of 500 mA g−1 in 0.0-3.0 V, LiCrTiO4 prepared at 800 °C still shows excellent cycling performance with a reversible capacity of 226.7 mAh g−1 after 80 cycles. Ex-situ valence analysis reveals that the high lithium storage capacity in LiCrTiO4 between 0.0 and 3.0 V is attributed to the reversible redox process of Ti4+/Ti3+ and Cr3+/Cr2+ couples. In addition, quasi zero-strain characteristic of LiCrTiO4 during lithiation is also demonstrated by in-situ and ex-situ structural observations. Therefore, LiCrTiO4 exhibits high structural stability and electrochemical reversibility as anode material for rechargeable lithium-ion batteries.

By using a simple high temperature solid state reaction, LiNi0.6Co0.2Mn0.1Al0.1O2 is prepared via Ni site dual substitution with Mn and Al. Structural observation reveals that the as-prepared sample can be indexed to an α-NaFeO2 type single phase with R-3m space group. Morphology and particle size investigations present that Mn and Al co-doped LiNi0.8Co0.2O2 is composed of micro-sized secondary particles (5–20 μm) agglomerated from highly packed primary particles (1–2 μm). Charge–discharge tests demonstrate that LiNi0.6Co0.2Mn0.1Al0.1O2 can reversibly react with lithium between 2.5 and 4.9 V with a high discharge capacity of 202.0 mAh g−1. This favorable electrochemical performance is attributed to the stable crystal structure after Mn and Al dual doping. This quasi-reversible structural change is also proved by in-situ X-ray diffraction study in this work.

In consideration of the abundance of sodium resources, sodium ion batteries (SIBs) have been revisited recently and are considered as a substitution for lithium ion batteries (LIBs). Among all the proposed anodes for SIBs, metal selenides labeled as high theoretical capacity materials have aroused the interest of battery researchers. However, as conversion/alloying based electrode materials, metal selenides suffer from a severe volume change during cycling, thus leading to kinetic problems and poor electrochemical stability, which restrain their further application in SIBs. Therefore, modification strategies such as coupling with carbonaceous material, designing unique structure, selecting an upper cut-off voltage, optimizing the composition of electrolyte, controlling the composition of the material etc. have been adopted to alleviate the volume change issue of metal selenides electrodes. In this article, the research progresses on the metal selenides as electrodes for SIBs are comprehensively reviewed and the difference and necessity of each metal selenide from the perspectives of structure and conductivity are emphasized. The summarization of metal selenides contains the synthesis methods, modification methods for performance improvement, corresponding reaction mechanism and performance in full-cell system. Finally, a conclusion with the challenges and outlook of metal selenides in the field of SIBs is also presented.