A Li3V2(PO4)3/C thin film with high rate capability as a cathode material for lithium-ion batteries

A monoclinic lithium vanadium phosphate (Li₃V₂(PO₄)₃) and carbon composite thin film (LVP/C) is prepared via electrostatic spray deposition. The film is studied with X-ray diffraction, scanning and transmission electron microscopy and galvanostatic cell cycling. The LVP/C film is composed of carbon-coated Li₃V₂(PO₄)₃ nanoparticles (50 nm) that are well distributed in a carbon matrix. In the voltage range of 3.0–4.3 V, it exhibits a reversible capacity of 118 mA h g^?1 and good capacity retention at the current rate of 1 C, while delivers 80 mA h g^?1 at 24 C. These results suggest a practical strategy to develop new cathode materials for high power lithium-ion batteries.     

Comparison of the electrochemical properties of metallic layered nitrides containing cobalt,nickel and copper in the 1 V–0.02 V potential range

We report the first example of an intercalation compound based on the nitrogen framework in which lithium can be intercalated and deintercalated. A comparison of the structural and electrochemical properties of the ternary lithium cobalt, nickel and copper nitrides is performed. Vacancy layered structures of ternary lithium nitridocobaltates Li_3−2xCo_xN and nitridonickelates Li_3−2xNi_xN with 0.10 ⩽ x ⩽ 0.44 and 0.20 ⩽ x ⩽ 0.60, respectively, are proved to reversibly intercalate Li ions in the 1 V–0.02 V potential range. These host lattices can accommodate up to 0.35 Li ion par mole of nitride. Results herein obtained support Li insertion in vacancies located in Li₂N⁻ layers while interlayer divalent cobalt and nickel cations are reduced to monovalent species. No structural strain is induced by the insertion–extraction electrochemical reaction which explains the high stability of the capacity in both cases. For the Li_1.86Ni_0.57N compound, a stable faradaic yield of 0.30 F/mol, i.e. 130 mAh/g, is maintained at least for 100 cycles. Conversely, the ternary copper nitrides corresponding to the chemical composition Li_3−xCu_xN with 0.10 ⩽ x ⩽ 0.40 do not allow the insertion reaction to take place due to the presence of monovalent copper combined with the lack of vacancies to accommodate Li ions. In the latter case, the discharge of the lithium copper nitrides is not reversible.     

Self-assembled Li4Ti5O12/TiO2/Li3PO4 for integrated Li–ion microbatteries

This work aims to maximize the number of active sites for energy storage per geometric area, by approaching the investigation to 3D design for microelectrode arrays. Self-organized Li₄Ti₅O₁₂/TiO₂/Li₃PO₄ composite nanoforest layer (LTL) is obtained from a layer of self organized TiO₂/Li₃PO₄ nanotubes. The electrochemical response of this thin film electrode prepared at 700 °C exhibited lithium insertion and de-insertion at 1.55 and 1.57 V respectively, which is the typical potential found for lithium titanates. The effects of lithium phosphate on lithium titanate are explored for the first time. By cycling between 2.7 and 0.75 V the LTL/LiFePO₄ full cell delivered 145 mA h g^− 1 at an average potential of 1.85 V leading to an energy density of 260 W h kg^− 1 at C/2. Raman spectroscopy revealed that the γ-Li₃PO₄/lithium titanate structure is preserved after prolonged cycling. This means that Li₃PO₄ plays an important role for enhancing the electronic conductivity and lithium ion diffusion.     

Preparation and electrochemical lithium storage of flower-like spinel Li4Ti5O12 consisting of nanosheets

In this paper, flower-like spinel Li₄Ti₅O₁₂ consisting of nanosheets was synthesized by a hydrothermal process in glycol solution and following calcination. The as-prepared product was characterized by scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction and cyclic voltammetry. The capacity of the sample used as anode material for lithium ion battery was measured. This structured Li₄Ti₅O₁₂ exhibited a high reversible capacity and an excellent rate capability of 165.8 m Ahg⁻¹ at 8 C, indicating potential application for lithium ion batteries with high rate performance and high capacity.     

InP as new anode material for lithium ion batteries

InP thin film has been successfully fabricated by pulsed laser deposition (PLD) and was investigated for its electrochemistry with lithium for the first time. InP thin film presented a large reversible discharge capacity around 620 mAh g^?1. The reversibility of the crystalline structure and electrochemical reaction of InP with lithium were revealed by using ex situ XRD and XPS measurements. The high reversible capacity and stable cycle of InP thin film electrode with low overpotential made it one of the promise energy storage materials for future rechargeable lithium batteries.     

Electrochemical characteristics of spinel Li4Ti5O12 discharged to 0.01 V

Cycling stability, reversible capacity and rate performance of Li₄Ti₅O₁₂ discharged to 0.01 V were investigated. A couple of obvious and repeatable peaks under 0.6 V observed by CV indicated that Li₄Ti₅O₁₂ possessed reversible capacity below 0.6 V. When discharge voltage of Li₄Ti₅O₁₂ extended from 0.6 to 0.01 V, its cycling stability was not affected and its reversible capacity and high rate performance were improved. Although the capacity obtained from 2.0 to 0.6 V gradually decreased with increasing the applied current density, the capacity obtained from 0.6 to 0.01 V showed little loss. AB was both electronic conducting additive and lithium-ion conducting additive for Li₄Ti₅O₁₂ under 0.6 V.     

Nano-structured Li3V2(PO4)3/carbon composite for high-rate lithium-ion batteries

Nano-structured Li₃V₂(PO₄)₃/carbon composite (Li₃V₂(PO₄)₃/C) has been successfully prepared by incorporating the precursor solution into a highly mesoporous carbon with an expanded pore structure. X-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy were used to characterize the structure of the composites. Li₃V₂(PO₄)₃ had particle sizes of < 50 nm and was well dispersed in the carbon matrix. When cycled within a voltage range of 3 to 4.3 V, a Li₃V₂(PO₄)₃/C composite delivered a reversible capacity of 122 mA h g^? 1 at a 1C rate and maintained a specific discharge capacity of 83 mA h g^? 1 at a 32C rate. These results demonstrate that cathodes made from a nano-structured Li₃V₂(PO₄)₃ and mesoporous carbon composite material have great potential for use in high-power Li-ion batteries.     

Sodium vanadium nitridophosphate Na3V(PO3)3N as a high-voltage positive electrode material for Na-ion and Li-ion batteries

We report the preparation and electrochemical properties of Na₃V(PO₃)₃N made by ammonolysis. Na₃V(PO₃)₃N is reversibly oxidized to Na₂V(PO₃)₃N at high voltage (4.0 V vs. Na⁺/Na⁰ and 4.1 V vs. Li⁺/Li⁰) with an unusually small difference in the insertion/extraction voltage between both alkali metal reference electrodes. In both cases, the voltage hysteresis is extremely small (~ 0.035 V vs. sodium and ~ 0.065 V vs. lithium), which suggests facile migration of alkali cations within the structure. Further oxidation to NaV(PO₃)₃N is predicted to occur beyond the voltage stability window of the electrolytes.     

Li0.93[Li0.21Co0.28Mn0.51]O2 nanoparticles for lithium battery cathode material made by cationic exchange from K-birnessite

Li_0.93[Li_0.21Co_0.28Mn _0.51]O₂ nanoparticles with an R-3m space group is hydrothermally prepared from Co_0.35Mn_0.65O₂ obtained from an ion-exchange reaction with K-birnessite K_0.32MnO₂ at 200 °C. Even at a hydrothermal reaction temperature of 150 °C, the spinel (Fd3m) phase is dominant, and a layered phase became dominant by combining an increase in the temperature to 200 °C with an increase in lithium concentration. The as-prepared cathode particle has plate-like hexagonal morphology with a size of 100 nm and thickness of 20 nm. The first discharge capacity of the cathode is 258 mAh/g with an irreversible capacity ratio of 22%, and the capacity retention after 30 cycles is 95% without developing a plateau at ∼3 V. Capacity retention of the cathode discharge is 84% at 4C rate (=1000 mA/g) and shows full capacity recovery when decreasing the C rate to 0.1 C.     

Structural and electrochemical investigation of Li2MgSnO4 anode for lithium batteries

Hexagonal Li₂MgSnO₄ compound was synthesized at 800 °C using Urea Assisted Combustion (UAC) method and the same has been exploited as an anode material for lithium battery applications. Structural investigations through X-ray diffraction, Fourier Transform Infra Red spectroscopy and ⁷Li NMR (Nuclear Magnetic Resonance spectroscopy) studies demonstrated the existence of hexagonal crystallite structure with a = 6.10 and c = 9.75. An average crystallite size of ∼400 nm has been calculated from PXRD pattern, which was further evidenced by SEM images. An initial discharge capacity of ∼794 mA h/g has been delivered by Li₂MgSnO₄ anode with an excellent capacity retention (85%) and an enhanced coulombic efficiency (97–99%). Further, the Li₂MgSnO₄ anode material has exhibited a steady state reversible capacity of ∼590 mA h/g even after 30 cycles, thus qualifying the same for use in futuristic lithium battery applications.     

Reversible lithium storage in Na2Li2Ti6O14 as anode for lithium ion batteries

The sodium lithium titanate with composition Na₂Li₂Ti₆O₁₄ has been synthesized by a sol–gel method. Thermogravimetric analysis and differential thermal analysis (TG–DTA) of the thermal decomposition process of the precursor and X-ray diffraction (XRD) data indicate the crystallization of sodium lithium titanate has occurred at about 600 °C. Electrochemical lithium insertion into Na₂Li₂Ti₆O₁₄ for lithium ion battery has been investigated for the first time. These results indicate the discharge and charge potential plateaus are about 1.3 V. The initial discharge capacity is much higher than the charge capacity and irreversible capacity exists in the voltage window 1–3 V. Subsequently, the discharge capacity decreases slowly, but the charge capacity increases slightly in the following cycles. After a few cycles, the specific capacity remains almost constant values and the sample exhibits the excellent retention of capacity on cycling.     

Structural and electrochemical properties of a porous nanostructured SnO2 film electrode for lithium-ion batteries

A B₂O₃-doped SnO₂ thin film was prepared by a novel experimental procedure combining the electrodeposition and the hydrothermal treatment, and its structure and electrochemical properties were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, energy dispersive X-ray (EDX) spectroscopy and galvanostatic charge–discharge tests. It was found that the as-prepared modified SnO₂ film shows a porous network structure with large specific surface area and high crystallinity. The results of electrochemical tests showed that the modified SnO₂ electrode presents the largest reversible capacity of 676 mAh g^?1 at the fourth cycle, close to the theoretical capacity of SnO₂ (790 mAh g^?1); and it still delivers a reversible Li storage capacity of 524 mAh g^?1 after 50 cycles. The reasons that the modified SnO₂ film electrode shows excellent electrochemical properties were also discussed.     

Nanocrystalline MnO thin film anode for lithium ion batteries with low overpotential

Nanocrystalline MnO thin film has been prepared by a pulsed laser deposition (PLD) method. The reversible lithium storage capacity of the MnO thin film electrodes at 0.125C is over 472 mAh g^?1 (3484 mAh cm^?3) and can be retained more than 90% after 25 cycles. At a rate of 6C, 55% value of the capacity at 0.125C rate can be obtained for both charge and discharge. As-prepared MnO thin film electrodes show the lowest values of overpotential for both charge and discharge among transition metal oxides. All these performances make MnO a promising high capacity anode material for Li-ion batteries.     

Sol–gel fabrication of lithium-ion microarray battery

Microarray electrodes of LiMn₂O₄ and Li_4/3Ti_5/3O₄ were prepared on a glass substrate using a sol–gel method. The prepared LiMn₂O₄ and Li_4/3Ti_5/3O₄ microarray electrodes were characterized with scanning electron microscopy, Raman spectroscopy, and cyclic voltammetry. Using a polymer-gel electrolyte, lithium ion microbattery of Li_4/3Ti_5/3O₄/polymer-gel/LiMn₂O₄ (cell area: 6.6 × 10⁻² cm²) was successfully constructed. The microbattery operated reversibly at 2.5 V, and the discharge capacity was 300 nA h, which corresponded to an energy density of 11 μW h cm⁻².     

A hierarchical micro/nanostructured 0.5Li2MnO3·0.5LiMn0.4Ni0.3Co0.3O2 material synthesized by solvothermal route as high rate cathode of lithium ion battery

A hierarchical micro/nanostructured Li-rich layered 0.5Li₂MnO₃·0.5LiMn_0.4Ni_0.3Co_0.3O₂ (H-LMNCO) material is prepared for the first time through the development of a solvothermal method, and served as cathode of lithium ion batteries. Electrochemical tests indicate that the H-LMNCO exhibits both a high reversible capacity and an excellent rate capability. The reversible discharge capacity of the H-LMNCO has been measured as high as 300.1 mAh·g^− 1 at 0.2 C rate. When the rate is increased to 10 C, the discharge capacity could still maintain a high value of 163.3 mAh·g^− 1. The results demonstrate that the developed solvothermal route is a novel synthesis strategy of preparing high rate performance Li-rich layered cathode material for lithium ion batteries.     

A room temperature solid-state rechargeable sodium ion cell based on a ceramic Na-β″-Al2O3 electrolyte and NaTi2(PO4)3 cathode

In this work, a room temperature solid-state rechargeable sodium ion cell, consisting of a ceramic Na-β″-Al₂O₃ thin film as the electrolyte, a NaTi₂(PO₄)₃ gel composite as the cathode and sodium metal as the anode, was developed for the first time. A dense Na-β″-Al₂O₃ thin film with a thickness of approximately 100 μm was obtained by non-toxic and hazard-free ceramic fabrication processes, including tape-casting and subsequent sintering. The solid-state sodium ion cell had a working window of 1.5–2.5 V upon charge-discharge processes and exhibited an extremely stable voltage plateau of approximately 2.1 V. A reversible capacity, based on the NaTi₂(PO₄)₃ cathode, of 133 mAh g^− 1 was observed during the first cycle, which remained approximately 100 mAh g^− 1 after 50 cycles.     

Electrochemical reduction of nano-SiO2 in hard carbon as anode material for lithium ion batteries

A composite of silica (SiO₂) and hard carbon was prepared by hydrothermal reaction. Special attention was paid to the characterization of the possible electrochemical reduction of nano-SiO₂ in the composite. Evidence by solid-state nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) and high lithium storage capacity of the composite prove the electrochemical reduction of nano-SiO₂ and the formation of Li₄SiO₄ and Li₂O as well as Si in the first-discharge. The reversible lithium storage capacity of the nano-SiO₂ is as high as 1675 mAh/g.     

Low-temperature growth of vertically aligned In2O3 nanoblades with improved lithium storage properties

Vertically aligned Indium oxide (In₂O₃) nanoblades are successfully obtained through plasma enhanced chemical vapor deposition (PECVD) approach. By using plasma, the reaction between InCl₃ and O₂ was able to take place, yielding vertically aligned blade like nanostructure. The novel In₂O₃ nanostructures exhibit improved electrochemical properties when used as anode materials for lithium-ion batteries. The In₂O₃ electrode reveals reversible capacity of 580 mAh g^?1 after 100 cycles, much higher than that of the In₂O₃ thin films. The result suggests that proper structural modification of In₂O₃ thin film may contribute to the improvement of electrochemical properties. The In₂O₃ electrodes with large reversible capacity and stable cycling performance may provide new insight of anode materials applied in thin film lithium-ion batteries.     

LiMn2O4 hollow nanosphere electrode material with excellent cycling reversibility and rate capability

Lithium-rich Li_1.05Mn₂O₄ hollow nanospheres have been successfully prepared by air-calcining lithiated MnO₂ precursor at a low temperature of 550 °C, which was synthesized by chemical lithiation of hollow MnO₂ nanospheres with LiI at 70 °C for 12 h. The lithium-rich Li_1.05Mn₂O₄ hollow nanospheres exhibit an excellent cycling stability and rate capability as a cathode material for rechargeable lithium batteries: it maintains 90% of its initial capacity after 500 cycles, and keeps 70% of the reversible capacity at 0.1 C rat, even at 15 C rate.     

Li2SO4-polyacrylamide polymer electrolytes for 2.0 V solid symmetric supercapacitors

A neutral polymer electrolyte comprised of lithium sulfate (Li₂SO₄) and polyacrylamide (PAM) was developed. The Li₂SO₄-PAM electrolyte film shows an ionic conductivity up to 10 mS cm^− 1 in 45%RH conditions. Solid double layer capacitors were demonstrated using CNT-graphite electrodes and Li₂SO₄-PAM solid electrolytes. The voltage window of the solid cell was about 2.0 V, identical to that of a Li₂SO₄ liquid cell used as baseline. The demonstrated voltage window is significantly larger than that reported for proton- or hydroxyl-conducting electrolytes, suggesting that the Li₂SO₄-PAM electrolyte is a promising system for high energy density supercapacitors. The solid device also demonstrated excellent rate capability (up to 5 V s^− 1) and good cycle life (beyond 10,000 charge/discharge cycles).