High rate performance of lithium manganese nitride and oxynitride as negative electrodes in lithium batteries

The performance of Li_7.9MnN_3.2O_1.6 and Li₇MnN₄ as electrode materials in lithium batteries was analyzed. At 1C rate, capacities of 180 and 230 mAh/g, respectively, were obtained after 50 cycles. If the first charge is done at 0.1C, outstanding capacities of 120–135 mAh/g are observed after 100 cycles at 5C. More lithium can be removed during the charge at 0.1C, leading to a large amount of lithium vacancies that enhance mobility and rate capability. It is proposed that incomplete filling of the vacancies occurs upon cycling, so that the mobility remains high. This performance compares well to that of Li₄Ti₅O₁₂.     

Tunable lithium storage properties of metal lithium titanates by stoichiometric modulation

A simple stoichiometric modulation of Na_2 − 2xSr_xLi₂Ti₆O₁₄ was developed to achieve tunable electrochemical properties of the material. The concept was confirmed experimentally and theoretically using density functional theory (DFT) calculations. Both the operating potential and the amount of reversibly intercalated lithium ions were manipulated by simply changing the Na/Sr ratio. These unique characteristics originated from a gradual change in the electron density on the Ti atoms and the extra lithium insertion sites at SrLi₂Ti₆O₁₄. As a promising anode material for lithium-ion batteries, Na_2 − 2xSr_xLi₂Ti₆O₁₄ and its tunable electrochemical properties have significant importance in terms of the development of tailored electrodes with desirable electrochemical performance.     

Nb2O5 nanobelts: A lithium intercalation host with large capacity and high rate capability

In this study, Nb₂O₅ nanobelts, with a ca. ∼15 nm in thickness, ca. ∼60 nm in width and several tens of mircrometers in length, have first been used as the electrode material for lithium intercalation over the potential window of 3.0–1.2 V (vs. Li⁺/Li). It delivers an initial intercalation capacity of 250 mA hg⁻¹ at 0.1 Ag⁻¹ current density, corresponding to x = 2.5 for L_xNb₂O₅, and can still keep relative stable and reaches as large as 180 mA hg⁻¹ after 50 cycles. Surprisingly, the electrodes composed of Nb₂O₅ nanobelts can work smoothly even at high current density of 10 Ag⁻¹, and shows higher specific capacity and excellent cycling stable, as well as sloped feature in voltage profile. Cycling test indicates Nb₂O₅ nanobelts electrode shows a high reversible charge/discharge capacity, high rate capability with excellent cycling stability.     

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.     

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.     

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.     

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.     

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.     

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.     

Lithium storage in hollow spherical ZnFe2O4 as anode materials for lithium ion batteries

Hollow microspheres composed of phase-pure ZnFe₂O₄ nanoparticles (hierarchically structured) have been prepared by hydrothermal reaction. The unique hollow spherical structure significantly increases the specific capacity and improves capacity retention of this material. The product of each phase transition during initial discharge (ZnFe₂O₄ ? Li_0.5ZnFe₂O₄ ? Li₂ZnFe₂O₄ → Li₂O + Li–Zn + Fe) and their structural reversibility are recognized by X-ray diffraction and electrochemical characterization. The products of the deeply discharged (Li–Zn alloy and Fe) and recharged materials (Fe₂O₃) were clarified based on high resolution transmission electron microscopic technique and first-principle calculations.     

Li(4−x)/3Ti(5−2x)/3CrxO4 (0 ≤ x ≤ 0.9) spinels: New negatives for lithium batteries

Members of the spinel solid solution between Li_4/3Ti_5/3O₄ and LiCrTiO₄, i.e., Li_(4−x)/3Ti_(5−2x)/3Cr_xO₄ (0 ≤ x ≤ 0.9), have been investigated as possible negative electrodes for future lithium-ion batteries. Electrochemical behaviour have been studied over the potential range 1–3.5 V vs Li⁺/Li. Results are promising with anodic capacities between 129 and 163 mA h/g with a flat operating voltage at about 1.5 V, which is attributed to the pair Ti⁴⁺/Ti³⁺. The inclusion of Cr³⁺ in the spinel structure enhances the specific capacity. In-situ X-ray diffraction experiments confirm that the reaction proceeds in a topotactic manner.     

Perfect reversibility of the lithium insertion in FeS2: The combined effects of all-solid-state and thin film cell configurations

All-solid-state thin film batteries based on sputtered pyrite electrodes, a lithium phosphorus oxynitride electrolyte and a lithium anode were prepared and characterized. The successive reduction of both S₂^2 − and Fe^2 + species led to an impressive volumetric discharge capacity, five times higher than the one for LiCoO₂. Excellent reversibility and capacity retention were obtained during the first and the subsequent 800 charge–discharge cycles. A continuous cycling in the low voltage domain was found to be detrimental to the reversibility of the conversion reaction, suggesting a progressive evolution of the phase distribution inside the electrode. The initial capacity was easily recovered after few full oxidation cycles.     

Lithium storage in perovskite lithium lanthanum titanate

Perovskite lithium lanthanum titanate (LLTO) was synthesized using sol–gel method. It shows a reversible capacity of 145 mA h g^− 1 and moderate cycling performance between 0.01 and 2.00 V. Cyclic voltammetry and X-ray diffraction results demonstrate a two-step solid–solution reaction behavior in the voltage range of 0.00–3.00 V upon lithium insertion/extraction. A stable solid electrolyte interphase (SEI) layer is formed on the surface of LLTO after the initial discharge. Carbon coating by chemical vapor deposition improves its cycling performance significantly.     

Synthesis and properties of a lithium-organic coordination compound as lithium-inserted material for lithium ion batteries

A lithium-organic coordination compound based on an aromatic carbonyl derivative, [Li₂(C₁₄H₆O₄)], was synthesized by the dehydration of [Li₂(C₁₄H₆O₄)·H₂O], and used as a novel lithium-inserted material for lithium ion batteries. The synthesized material has initial discharge capacity of 126 and 115 mAh/g at current densities of 22 and 111 mAh/g, corresponding to the columbic efficiency of 99.2% and 98.3% at the first cycle, and its capacity fading is only 5% and 13% after 50 cycles, respectively, showing that this compound is a promising candidate as lithium-inserted material for lithium ion batteries.     

A novel anode material of antimony nitride for rechargeable lithium batteries

Antimony nitride thin film has been successfully fabricated by magnetron sputtering method and its electrochemistry with lithium was investigated for the first time. The reversible discharge capacity of Sb₃N/Li cells cycled between 0.3 V and 3.0 V was found above 600 mAh/g. By using transmission electron microscopy and selected area electron diffraction measurements, the conversion reaction of Sb₃N into Li₃Sb and Li₃N was revealed during the lithium electrochemical reaction of Sb₃N thin film electrode. The high reversible capacity and the good cycleability made Sb₃N one of promising anode materials for future rechargeable lithium batteries.     

Low charge overpotentials and extended full cycling capability in lithium-oxygen batteries by controlling the nature of discharge products

Hollow NiCo₂O₄ microspheres with a highly hierarchical porous structure were synthesized and conducted as catalysts for lithium-oxygen batteries. The influence of NiCo₂O₄ on the discharge products was investigated. The NiCo₂O₄ showed the capability to promote the formation of lithium deficient Li_2 − xO₂ and exerted a significant influence on the electrochemical performance of lithium-oxygen batteries with a low charge overpotential and extended full cycling over 50 cycles.     

Lithia formation mechanism in tin oxide anodes for lithium–ion rechargeable batteries

The lithia formation mechanism in tin oxide anode is investigated using electrochemical measurements and Auger spectroscopy. Based on the charge/discharge capacities for SnO electrode, the atomic ratio of Li to O in lithia is less than 2 at the discharge capacity of 400 mAh/g (～0.9 V). The derivative capacity plots show that the irreversible reaction occurs throughout the entire discharge to 0 V, and the atomic ratio of Li to O is about 1 at ～0.8 V and 2 at 0 V. Auger spectroscopy analysis also confirms that the atomic ratio of Li to O approaches to 2 only when discharged to 0 V. Thus, Li₂O appears to have formed at 0 V in the first discharge, not ～0.8 V as reported previously, such that the initial lithia composition is more like Li₂O₂.     

Li4Ti5O12/reduced graphite oxide nano-hybrid material for high rate lithium-ion batteries

A spinel Li₄Ti₅O₁₂ nanoplatelet/reduced graphite oxide nano-hybrid was successfully synthesized by a two-step microwave-assisted solvothermal reaction and heat treatment. The Li₄Ti₅O₁₂ in the hybrid could deliver a discharge capacity of 154 mAhg^? 1 of Li₄Ti₅O₁₂ at 1 C-rate, 128 mAhg^-1 of Li₄Ti₅O₁₂ at 50 C-rate and 101 mAhg^-1 of Li₄Ti₅O₁₂ at 100 C-rate. It demonstrated promising potential as an anode material in a Li-ion battery with excellent rate capability and good cycling.     

Novel concept of pseudocapacitor using stabilized lithium metal powder and non-lithiated metal oxide electrodes in organic electrolyte

A concept of using two non-prelithiated metal oxides (e.g., MnO₂, V₂O₅, and FeO_x) in both positive and negative electrodes in organic Li-ion electrolytes has been proposed and tested to improve the energy density of pseudocapacitors. To take the advantages of this concept, additional lithium source is essential to provide lithium ions during the charge–discharge cycles. The stabilized lithium metal powder (SLMP^?) developed by FMC Corp., provides such an essential Li⁺ source. Here we report the first result of the symmetric pseudocapacitor using two non-prelithiated metal oxide (i.e., manganese oxide/carbon nanotube (MnO₂/CNT)) electrodes, with added SLMP in one of them. The capacitor using the SLMP added MnO₂/CNT (positive) and pure MnO₂/CNT (negative) electrode in 1.2 M LiPF₆-EC:EMC electrolyte shows supercapacitive behaviors in 3.0 V voltage range. The addition of SLMP opens new opportunities of using the non-lithiated metal oxide electrodes in pseudocapacitors and hybrid electrochemical capacitors (ECs), which has not been possible before.     

High capacity Li[Li0.2Mn0.54Ni0.13Co0.13]O2–V2O5 composite cathodes with low irreversible capacity loss for lithium ion batteries

With an aim to suppress the huge irreversible capacity loss encountered in high capacity layered oxide solid solutions between Li₂MnO₃ and LiMO₂ (M = Mn, Ni, and Co), layered Li[Li_0.2Mn_0.54Ni_0.13Co_0.13]O₂–V₂O₅ composite cathodes with various V₂O₅ contents have been investigated. The irreversible capacity loss decreases from 68 mAh/g at 100% Li[Li_0.2Mn_0.54Ni_0.13Co_0.13]O₂ to 0 mAh/g around 89 wt.% Li[Li_0.2Mn_0.54Ni_0.13Co_0.13]O₂–11 wt.% V₂O₅ as the lithium-free V₂O₅ serves as an insertion host to accommodate the lithium ions that could not be inserted back into the layered lattice after the first charge. The Li[Li_0.2Mn_0.54Ni_0.13Co_0.13]O₂–V₂O₅ composite cathodes with about 10–12 wt.% V₂O₅ exhibit an attractive discharge capacity of close to 300 mAh/g with little irreversible capacity loss and good cyclability.