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Among a variety of host materials for lithium storage, titanium-niobium oxides exhibit great potential in application. Herein, Ti 2 Nb 10 O 29 nanowire is synthesized via an electrospinning method. Compared with bulk Ti 2 Nb 10 O 29 prepared by solid-state approach, the electrochemical properties of Ti 2 Nb 10 O 29 nanowire is better. According to the galvanostatic charging-discharging test, the initial capacity of 232.8 mAh g−1 for Ti 2 Nb 10 O 29 nanowire is displayed. Besides, it exhibits superior rate performance. With the current density set as 0.5, 1, 2, 3, 4 and 5 C, the Ti 2 Nb 10 O 29 nanowire can deliver the specific capacity of 251.3, 240.3, 221.8, 205.3, 188.1 and 174.5 mAh g−1, respectively. Furthermore, its cycling performance is superior. The capacity retention of Ti 2 Nb 10 O 29 nanowire is 85.90% after 900 cycles at 12 C, which is obviously superior than that of bulk Ti 2 Nb 10 O 29 (25.16%). Finally, a Ti 2 Nb 10 O 29 /LiCoO 2 full cell is fabricated, which exhibits excellent electrochemical performance, demonstrating its potential for practical application. [ABSTRACT FROM AUTHOR]

Herein, we propose a new anode material, PbNb 2 O 6 , for use in lithium-ion batteries. PbNb 2 O 6 can be synthesized via a simple and traditional solid-state method. The as-prepared powder exhibits an average size distribution of about 0.5 μm. When tested in a lithium-ion cell, the PbNb 2 O 6 electrode can exhibit a charge capacity of 245.2 mAh g−1 at 200 mA g−1, and after 80 cycles, the capacity can retain a charge capacity of 181.4 mAh g−1, showing 0.32% capacity fading per cycle. Furthermore, the capacity of the PbNb 2 O 6 electrode is 223.1 mAh g−1, even when cycled at 1000 mA g−1, and a capacity of 150.7 mAh g−1 is maintained up to 500 cycles. In addition, the lithiation mechanism of PbNb 2 O 6 is investigated via various techniques. Interestingly, PbNb 2 O 6 exhibits high capacity without the contribution of two redox couples of niobium after the initial cycles. Finally, all Results suggest that PbNb 2 O 6 has potential for use as an electrode in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • AgNb 13 O 33 is synthesized and applied as lithium host for the first time. • AgNb 13 O 33 shows a high storage capacity of 329.4 mAh g−1 above 1.0 V. • Structural evolutions of AgNb 13 O 33 are investigated by in-situ and ex-situ routes. Abstract Anode materials for lithium ion batteries with environmental benignity and great electrochemical performance are greatly desired. In this work, AgNb 13 O 33 with open framework is reported as an anode material for the first time. It shows a triclinic lattice with 4i, 4f sites and 8j sites for lithium storage. At the current density of 100 mA g−1, AgNb 13 O 33 delivers high initial charge/discharge capacity of 329.4/357.8 mAh g−1 with an initial Columbic efficiency of 92.06%. 500 cycles later, it still remains a reversible capacity of 214.2 mAh g−1. Moreover, at a higher rate of 1000 mA g−1, AgNb 13 O 33 still maintains an initial charge capacity of 203 mAh g−1. Ex-situ transmission electron microscope (TEM) and in-situ X-ray diffraction (XRD) tests are performed to study the lithiation and delithiation reactions of AgNb 13 O 33 during the cycling. The reversibility and structural stability of the AgNb 13 O 33 make contributions to its excellent performance. All results show the promising possibility of applying AgNb 13 O 33 as an anode material for lithium ion batteries. [ABSTRACT FROM AUTHOR]

Lithium ion batteries (LIBs), sodium ion batteries (SIBs) and potassium ion batteries (PIBs) can be proposed as substitutes to fossil fuels because of the gradual depletion of non-renewable energy. In this work, Pb 3 Nb 4 O 13 is investigated as a new kind of anode material with the storage ability of lithium, sodium and potassium. Pb 3 Nb 4 O 13 nanowires are prepared via a feasible electrospinning technique followed with calcinations. Furthermore, it's the first time for Pb 3 Nb 4 O 13 to be applied as anode materials. At the current density of 50 mA g −1 , Pb 3 Nb 4 O 13 shows reversible capacities of 264.8, 171.4 and 100.1 mA h g −1 in the applications of LIBs, SIBs and PIBs, respectively. In addition, the storage mechanisms of Pb 3 Nb 4 O 13 in different batteries are also investigated by in situ XRD. The results show that Pb 3 Nb 4 O 13 nanowires have the reversible conversion reactions between PbO 2 and Pb. This work perfectly confirms that Pb 3 Nb 4 O 13 nanowires might be a potential anode material for LIBs, SIBs and PIBs. [ABSTRACT FROM AUTHOR]

To fulfill the requirement for large-scale energy-storage systems, lithium ions batteries have been attracted great attentions. It is necessary to develop the anode material with high rate capability, long cycling life and outstanding safety. Here, N-doped carbon been successfully synthesized and estimated as an anode material for lithium ions batteries. PbLi 2 Ti 6 O 14 is isostructural with SrLi 2 Ti 6 O 14 . After nitrogen-doped carbon coating, PbLi 2 Ti 6 O 14 @NC delivers a high capacity of 143.2 mAh g −1 at a current density of 100 mA g −1 and remains 104.8 mAh g −1 even at 700 mA g −1 . In addition, PbLi 2 Ti 6 O 14 @NC also possesses excellent cyclic stability. The reversible capacity of PbLi 2 Ti 6 O 14 @NC can keep at 99.7 mAh g −1 after 1500 cycles. Such results are also proved by CV tests and EIS measurements. Meanwhile, the lithium storage mechanism of PbLi 2 Ti 6 O 14 @NC is investigated by an in situ XRD technique. It indicates that PbLi 2 Ti 6 O 14 @NC has a stable structural host. These aforementioned results suggest that PbLi 2 Ti 6 O 14 @NC has great potential working as an anode material for lithium ions batteries. [ABSTRACT FROM AUTHOR]

The preparation and characterization of Pb 1- x Ba x Li 2 Ti 6 O 14 ( 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 Pb 1- x Ba x Li 2 Ti 6 O 14 . 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 Pb 1- x Ba x Li 2 Ti 6 O 14 ( 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 Pb 1- x Ba x Li 2 Ti 6 O 14 and its initial charge capacity increases reversely. Moreover, different Pb/Ba atomic ratio also brings different cycling stability for Pb 1- x Ba x Li 2 Ti 6 O 14 . Especially for Pb 3/4 Ba 1/4 Li 2 Ti 6 O 14 , it presents better electrochemical properties than other samples. After 120 cycles, the reversible capacity of Pb 3/4 Ba 1/4 Li 2 Ti 6 O 14 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In order to investigate the lithiation-delithiation kinetics in BaLi 2 Ti 6 O 14 anode material, BaLi 2 Ti 6 O 14 is achieved by a solid-state reaction process in this work. The as-prepared BaLi 2 Ti 6 O 14 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 BaLi 2 Ti 6 O 14 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 BaLi 2 Ti 6 O 14 is investigated by cyclic voltammetry (CV), in-situ electrochemical impedance spectroscopy ( in-situ EIS) and galvanostatic intermittent titration (GITT) techniques. The D Li + values calculated from CVs are located in the range of 10 − 13 –10 − 12 cm 2 s − 1 . For comparison, the average D Li + values received from EIS and GITT methods are located in the range of 10 − 14 –10 − 12 cm 2 s − 1 and 10 − 14 –10 − 11 cm 2 s − 1 , respectively. Although the D Li + differs by several orders of magnitude from different measurement techniques, it still reveals higher value than that of Li 4 Ti 5 O 12 . Owing to the rapid diffusion kinetics of BaLi 2 Ti 6 O 14 , symmetrical structural evolutions can be observed via in-situ X-ray diffraction (XRD) study, which indicates that BaLi 2 Ti 6 O 14 is a promising high-power anode candidate. [ABSTRACT FROM AUTHOR]

• low strain character of orthorhombic Na 2 TiSiO 5. • synergic diffusion of Na+ and Ti4+. • An insulator-metal transition is observed upon the intercalation of Li+. • Li+ intercalation mechanism, diffusion barriers and phase evolution are determined. As a member of silicate anode materials, orthorhombic Na 2 TiSiO 5 , synthesized by solid state method, has excellent electrochemical properties and is a promising Lithium-ion battery anode material with long cycle stability and low strain. At a current density of 100 mA g−1, Na 2 TiSiO 5 has a reversible capacity of 395.2 mA h g−1 after 200 cycles with Coulombic efficiencies more than 97%. A reversible capacity of 251.3 mA h g−1 after 1000 cycles is retained with Coulombic efficiencies more than 98%. ex-situ experiments show the high structural stability and a less than 0.67% change of unit cell parameters in the charge/discharge process. The bond valence energy landscape (BVEL) calculation reveals 12 voids, namely, 4c-1, 4c-2, 2b and 2a, in a unit cell. That corresponds to a nominal composition Na 2 Li(4c-1)Li(4c-2)Li 0.5 (2b)Li 0.5 (2a)TiSiO 5 and a theoretical capacity of 398.1 mAh g−1. The ab initio molecular dynamics (AIMD) simulations and density functional theory (DFT) calculations show that for both primitive orthorhombic Na 2 TiSiO 5 and Li+ inserted Na 2 TiSiO 5 , Na+/Li+ are not active. However, with the insertion of 4C Li+, the occurrence of the synergic diffusion of Na+ and Ti4+ (4c Na+ -> 4c Ti4+ and 4c Ti4+ -> 2b vacancy) reliefs the extra strain, improves the structural stability during charge/discharge. The formation energy convex hull reveals 3 intermediate phases, that is Na 2 LiTiSiO 5 , Na 2 Li 2 TiSiO 5 and Na 2 Li 2.75 TiSiO 5 , in the charge/discharge process. ex-situ X-ray diffraction scanning at 14 different charge-discharge stages showing low strain character of the material during the charge/discharge [Display omitted] [ABSTRACT FROM AUTHOR]

As a novel anode material, PbLi 2 Ti 6 O 14 is prepared by a traditional solid state method at a calcination temperature of 900 °C. Structural analysis and electrochemical tests prove that PbLi 2 Ti 6 O 14 possesses a good crystallinity and superior performance. PbLi 2 Ti 6 O 14 , composed of particles with 400 nm in length and 300 nm in width, exhibits an initial charge capacity of 155.1 mAh g −1 at 100 mA g −1 and maintains at 147.9 mAh g −1 after 100 cycles, with capacity retention as high as 95.4%. Especially, the reversible capacity of PbLi 2 Ti 6 O 14 can stabilize at 101.6 mAh g −1 after 1000 cycles at a high current density of 1000 mA g −1 , with capacity retention of 87.5%. Besides, the lithium storage behavior in PbLi 2 Ti 6 O 14 is also studied by various in-situ and ex-situ methods. It is found that the lithiation/delithiation process in PbLi 2 Ti 6 O 14 is a highly reversible reaction. All these results demonstrate that PbLi 2 Ti 6 O 14 may be an impressive anode material in the near future. [ABSTRACT FROM AUTHOR]

In this paper, a series of Li 3-x Na x V 2 (PO 4 ) 3 (0 ≤ x ≤ 3) are prepared by a solid state reaction and systematically evaluated as anode materials for lithium-ion batteries. Structural analysis shows that the phase structure of Li 3-x Na x V 2 (PO 4 ) 3 changes along with the evolution of Na content. Charge-discharge tests exhibit that Li 3 V 2 (PO 4 ) 3 shows the highest initial charge specific capacity as high as 88.3 mAh g −1 among all the seven samples, and the reversible capacity is kept at 68.3 mAh g −1 after 45 cycles, corresponding to 77.3% of the initial charge capacity. With increasing of Na content in Li 3-x Na x V 2 (PO 4 ) 3 , the as-obtained sample show poorer lithium storage capability than Li 3 V 2 (PO 4 ) 3 . As a result, Na 3 V 2 (PO 4 ) 3 shows the inferior cycling performance than other Li 3-x Na x V 2 (PO 4 ) 3 . It can only deliver a reversible capacity of 20.9 mAh g −1 after 45 cycles, corresponding to 45.9% of the initial charge capacity. In-situ X-ray diffraction observations demonstrate that the poor electrochemical property of Na 3 V 2 (PO 4 ) 3 anode is due to the irreversible structural evolution during charge-discharge process. Therefore, reducing the Na 3 V 2 (PO 4 ) 3 phase in as-obtained sample is a feasible route to improve the lithium storage capability of Li 3-x Na x V 2 (PO 4 ) 3 . [ABSTRACT FROM AUTHOR]

In this work, Na 2 Ti 6 O 13 nanorods are prepared by a traditional solid state reaction and reported as anode materials for advanced lithium-ion batteries. The effect of calcining temperature on the size and electrochemical behavior of nanorodes is thoroughly described and compared within the temperature range of 800-1000 °C. It can be found that the size of nanorodes increases with the enhancing of calcining temperature. At 1000 °C, Na 2 Ti 6 O 13 nanorodes melt into big bulks, which exhibit poor ionic conductivity and low lithium storage capacity. Although Na 2 Ti 6 O 13 nanorodes with smaller size can be formed at 800 °C, its capacity retention is poor. In contrast, Na 2 Ti 6 O 13 nanorodes obtained at 900 °C reveal high reversible capacity, rapid lithium ion diffusion behavior and outstanding rate property. In-situ and ex-situ analyses reveal that the structural evolution of Na 2 Ti 6 O 13 during lithiation and delithiation process is quasi-reversible, which ensures the excellent electrochemical performance of Na 2 Ti 6 O 13 nanorods for repeated lithium storage. [ABSTRACT FROM AUTHOR]

To form BaLi 2 Ti 6 O 14 /Ag, highly dispersed Ag nanoparticles are successfully deposited on the surface of BaLi 2 Ti 6 O 14 by a simple chemical deposition method. The morphology, quantity and size of Ag nanoparticles in BaLi 2 Ti 6 O 14 /Ag composites are significantly influenced by the Ag coating contents. Electrochemical results show that Ag nanoparticles play a positive role in reducing redox polarization and improving electrical conductivity of BaLi 2 Ti 6 O 14 during lithiation/delithiation processes. Among all the as-obtained products, 6 wt.% Ag coated BaLi 2 Ti 6 O 14 shows the highest initial charge specific capacity of 160 mAh g −1 at the current density of 100 mA g −1 (1C), which is much higher than the 149.1 mAh g −1 for bare BaLi 2 Ti 6 O 14 . After 100 charge/discharge cycles, the reversible capacity can be maintained at 117.0 mAh g −1 . Moreover, this sample also shows excellent rate performance with high reversible charge capacities of 147.5, 139.7, 132.6, and 126.7 mAh g −1 at the rates of 2C, 3C, 4C and 5C, respectively. Compared with bare BaLi 2 Ti 6 O 14 , the superior electrochemical performance indicates that BaLi 2 Ti 6 O 14 /Ag can be a good anode material in lithium ion batteries. [ABSTRACT FROM AUTHOR]

In this work, Li 2 NaV 2 (PO 4 ) 3 is successfully synthesized by using a simple solid-state reaction method. Structural analysis shows that this sample is a hybrid product consisted of rhombohedral Li 3 V 2 (PO 4 ) 3 phase and rhombohedral Na 3 V 2 (PO 4 ) 3 phase As a cathode material for lithium ion batteries, Li 2 NaV 2 (PO 4 ) 3 exhibits an initial reversible capacity of 108.9 mAh g −1 at 35 mA g −1 in the potential range between 3.0 and 4.3 V, with an average working potential at 3.75 V. The lithium-ion diffusion coefficient in Li 2 NaV 2 (PO 4 ) 3 is measured to be 1.86–3.27 × 10 −15 cm 2 s −1 . In addition, the electrochemical reaction between Li 2 NaV 2 (PO 4 ) 3 and Li is also investigated by various in-situ and ex-situ techniques. Viewed from the in-situ and ex-situ results, it is concluded that the electrochemical reactions of Li 2 NaV 2 (PO 4 ) 3 with Li are associated with the formation of rhombohedral LiV 2 (PO 4 ) 3 phase and rhombohedral NaV 2 (PO 4 ) 3 phase during the lithium ion extraction process and its reverse lithium insertion process is reversible for structural evolution. The highly stable structure ensures the electrochemical reversibility of Li 2 NaV 2 (PO 4 ) 3 cathode material in lithium ion batteries. [ABSTRACT FROM AUTHOR]

Three Li 3-x Na x V 2 (PO 4 ) 3 (x=0.5, 1.5 and 2.0) samples are synthesized by a traditional solid-state reaction method in this work. Their phase composition, surface morphology and electrochemical property are described and compared by using various physical/chemical methods. Phase analysis results reveal that Li 2.5 Na 0.5 V 2 (PO 4 ) 3 consists of monoclinic Li 3 V 2 (PO 4 ) 3 , rhombohedral Li 3 V 2 (PO 4 ) 3 and rhombohedral Na 3 V 2 (PO 4 ) 3. While, both Li 1.5 Na 1.5 V 2 (PO 4 ) 3 and LiNa 2 V 2 (PO 4 ) 3 are the two-phase mixture consisted of rhombohedral Li 3 V 2 (PO 4 ) 3 and rhombohedral Na 3 V 2 (PO 4 ) 3 . Electrochemical testing results reveal that LiNa 2 V 2 (PO 4 ) 3 and Li 1.5 Na 1.5 V 2 (PO 4 ) 3 can deliver the initial discharge capacities of 101.4 mAh g −1 and 108.6 mAh g −1 with a long potential plateau at 3.69 V, respectively. In contrast, Li 2.5 Na 0.5 V 2 (PO 4 ) 3 presents an initial discharge capacity of 111.7 mAh g −1 with four potential plateaus. High lithium ion diffusion coefficient in Li 2.5 Na 0.5 V 2 (PO 4 ) 3 indicates that the existence of monoclinic Li 3 V 2 (PO 4 ) 3 phase can improve the ionic conductivity and then be responsible for good electrochemical performance. Besides, in-situ X-ray diffraction observation of LiNa 2 V 2 (PO 4 ) 3 demonstrates that the phase transition is not fully reversible but quasi-reversible during the lithiation-delithiation process. The partial irreversibility of structural evolution for LiNa 2 V 2 (PO 4 ) 3 induces the capacity loss upon repeated cycles. [ABSTRACT FROM AUTHOR]

Highlights: [•] Li4Ti5O12@C is prepared by a facile carbon coating strategy. [•] Amorphous carbon coating layer shows a thickness of 4–6nm. [•] Li4Ti5O12@C delivers a capacity of 160.6mAhg−1 at 20mAg−1 in 1.0–2.0V. [•] Li4Ti5O12@C displays a capacity of 205.1mAhg−1 at 1500mAg−1 in 0.0–2.0V. [ABSTRACT FROM AUTHOR]

Highlights: [•] Metal carbonates are probable anode materials for lithium ion batteries. [•] CoCO3/C composite can deliver an initial discharge capacity of 2096.6mAhg−1 . [•] Co, Li2CO3, Li2O, and low-valence carbon are final lithiated products for CoCO3. [ABSTRACT FROM AUTHOR]