Low-cost Lithium-ion Batteries Research Articles

Lignin-assisted exfoliation of molybdenum disulfide in aqueous media and its application in lithium ion batteries.

In this article, alkali lignin (AL)-assisted direct exfoliation of MoS2 mineral into single-layer and few-layer nanosheets in water is reported for the first time. Under optimized conditions, the concentration of MoS2 nanosheets in the obtained dispersion can be as high as 1.75 ± 0.08 mg mL(-1), which is much higher than the typical reported concentrations (<1.0 mg mL(-1)) using synthetic polymers or compounds as surfactants. The stabilizing mechanism primarily lies in the electrostatic repulsion between negative charged AL, as suggested by zeta-potential measurements. When the exfoliated MoS2 nanosheets are applied as electrode materials for lithium ion batteries, they show much improved electrochemical performance compared with the pristine MoS2 mineral because of the enhanced ion and electron transfer kinetics. This facile, scalable and eco-friendly aqueous-based process in combination with renewable and ultra-low-cost lignin opens up possibilities for large-scale fabrication of MoS2-based nanocomposites and devices. Moreover, herein we demonstrate that AL is also an excellent surfactant for exfoliation of many other types of layered materials, including graphene, tungsten disulfide and boron nitride, in water, providing rich opportunities for a wider range of applications.

Porous Li2C8H4O4 coated with N-doped carbon by using CVD as an anode material for Li-ion batteries

N-doped carbon coated lithium terephthalate (Li2C8H4O4) porous microspheres were applied as advanced organic anodes for low cost lithium ion batteries, showing improved coulombic efficiencies in the first cycle as well as enhanced rate performances.

Remarkable Charge-Discharge Mechanism for a Large Capacity in Fe-Containing Li2MnO3 Cathodes

Fe-containing lithium-rich layered manganese oxides are remarkable cathode materials, which can fabricate the high energy density and low-cost lithium-ion batteries. Here, we investigated thoroughly the charge-discharge mechanism for the large capacity in 0.7Li2MnO3-0.3LiFeO2. X-ray absorption spectroscopy (XAS) and soft-XAS measurements using synchrotron radiation revealed that the large capacity in 0.7Li2MnO3-0.3LiFeO2 was achieved mainly by the collaborative participation of Mn and oxygen ions in charge compensation. Mn ions changed to the valence states of +2 and/or +3 for discharged states near the surface after oxygen and Li had been removed simultaneously at 4.4 V. Charge compensation for charged states was also accomplished by the oxidizing oxide ions such as those in the formation of O22−. Redox reactions in Fe ions mainly occurred with initial charge-discharge. The crystal structure has been changed partially in these processes from layered rock-salt to spinel-like structures for the Li deintercalation, which was confirmed by selected area electron diffraction (SAED). We also found that the change of electronic states with valence modifications and drastic structural changes happened preferentially on the surface of the cathode electrode.

Cycling Performance of Low-Cost Lithium-Ion Batteries with LiFePO4 Cathode

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Synthesis and Performance of Nano MnO as an Anode Material for Lithium-Ion Batteries

Transition metal oxides,especially manganese monoxide(MnO),are being intensively studied as candidate anode materials for next generation lithium-ion batteries in high efficiency energy storage applications such as portable electronics,electric vehicles,and stationary electricity storage.In this paper, the MnC_2O_4·2H_2O precursor,prepared from KMnO_4 and ascorbic acid,was heat-treated to synthesize nano MnO by a solid-state reaction approach.X-ray diffraction(XRD) showed that the so-obtained MnO had a rock-salt structure with good crystallinity,and scanning electron microscopy(SEM) indicated that the primary particle size was about 50-100 nm,while the secondary particle size was about 400-600 nm.As an active material for lithium-ion batteries,the nano MnO material delivered a reversible capacity of 679.7 mAh ? g~(-1) with an initial columbic efficiency of 68.9%at a current density of 46.3 mA ? g~(-1).The specific discharge capacity slightly decreased from 584.5 to 581.5 mAh ? g~(-1) with a retention of 99.5%after 50 cycles at a current density of 141.1 mA·g~(-1).Moreover,the material was able to release a capacity of 290 mAh ? g~(-1) at current densities as high as 494.7 mA ? g~(-1)(corresponding to ~2C),which demonstrates reasonable rate performance and moderately fast charge/discharge capabilities.All of the above characteristics make nano MnO promising anode materials for developing high-capacity,long-life,low-cost, and environmentally-friendly lithium-ion batteries.

New-type low-cost cathode materials for Li-ion batteries: Mikasaite-type Fe2(SO4)3

In the present work, a new-type low-cost lithium ion battery cathode material, the Mikasaite-type iron sulfate, has been studied. It can be prepared by heating the water-containing iron sulfate raw chemicals in air atmosphere. The experimental results have shown that the oxidation and the reduction peaks are 3.92 and 3.37 V in the cyclic voltammogram, respectively, when the scanning rate is 0.05 mV s−1. The galvanostatic measurements have explored that the voltage plateau during charging is slightly less than 3.70 V and the discharge voltage plateau is 3.40 V for the first cycle and 3.50 V for the following cycles at 0.1 C rate. The discharge capacity in the first cycle can reach 116 mAh g−1, about 87 % of the theoretical capacity (134 mAh g−1). It is believed that the product in the fully discharged state is Li2Fe2(SO4)3. However, the insertion reaction is reversible only for the second lithium ion. During cycling, the reversible capacity remains about 60 mAh g−1. Further capacity fade is not found in the 20 discharge–charge cycles. The electrochemical impedance measurements have shown that there are two compressed semicircles in the Nyquist plots and a Warburg impedance in the low-frequency domain. The high-frequency semicircle is related with the electrode’s structural factor and the intermediate-frequency semicircle corresponds to the charge-transfer process.

Drastically Improved Performances of Graphite/Li1.26Mn0.52Fe0.22O2 Cell with Stepwise Pre-Cycling Treatment that Causes Peroxide Forming

Iron-containing lithium-rich layered manganese oxides are promising as cathode active materials for fabricating high energy density and low-cost lithium-ion batteries. We synthesized Li1.26Mn0.52Fe0.22O2 (or 0.7Li2MnO3·0.3LiFeO2) by using the co-precipitate-hydrothermal-calcination method. We then tested a graphite/Li1.26Mn0.52Fe0.22O2 cell after a stepwise pre-cycling treatment. The pre-cycling treatment drastically increased the specific capacity of the Li1.26Mn0.52Fe0.22O2 from 167 to 236 mAh g−1 at a current rate of 5 mA g−1. Other cell performances, such as operation voltage, discharge rate capability, and cyclability, also improved with this treatment. An analytical study using gas chromatography revealed that these improvements were derived from the suppression of oxygen release from the oxide lattice. X-ray absorption spectroscopy and X-ray photoelectron spectroscopy analyzes indicated that the main charge compensation mechanism of pre-cycling treatment was not the redox reaction of transition metals, such as Mn3+/Mn4+ and Fe3+/Fe4+, but the redox reaction of O2− accompanying O22− formation in the oxide lattice.

Modelling of Ion Transport in Solids with a General Bond Valence Based Force-Field

Empirical bond length - bond valence relations provide insight into the link between structure of and ion transport in solid electrolytes. Building on our earlier systematic adjustment of bond valence (BV) parameters to the bond softness, here we discuss how the squared BV mismatch can be linked to the absolute energy scale and used as a general Morse-type interaction potential for analyzing low-energy pathways in ion conducting solid or mixed conductors either by an energy landscape approach or by molecular dynamics (MD) simulations. For a wide range of Lithium oxides we could thus model ion transport revealing significant differences to an earlier geometric approach. Our novel BV-based force-field has also been applied to investigate a range of mixed conductors, focusing on cathode materials for lithium ion battery (LIB) applications to promote a systematic design of LIB cathodes that combine high energy density with high power density. To demonstrate the versatility of the new BV-based force-field it is applied in exploring various strategies to enhance the power performance of safe low cost LIB materials (LiFePO 4 , LiVPO 4 F, LiFeSO 4 F, etc.). Received: 11 October 2010; Revised: 26 October 2010; Accepted: 28 October 2010

High power lithium ion battery materials by computational design

AbstractEmpirical bond length–bond valence (BV) relations provide insight into the link between structure of and ion transport in solid electrolytes and mixed conductors. Building on our earlier systematic adjustment of BV parameters to the bond softness, here we discuss how the squared BV mismatch is linked to the absolute energy scale and used as a general Morse‐type interaction potential for analyzing low‐energy ion migration paths in ion conducting solids or mixed conductors by either an energy landscape approach or molecular dynamics (MD) simulations. For a wide range of lithium oxides we could thus model ion transport revealing significant differences to an earlier geometric approach. This novel BV‐based force‐field has then been applied to investigate a range of mixed conductors, focusing on cathode materials for lithium ion battery (LIB) applications to promote a systematic design of LIB cathodes that combine high energy density with high power density. To demonstrate the versatility of the new BV‐based force field it is applied in exploring various strategies to enhance the power performance of safe low cost LIB materials including LiFePO4, LiVPO4F, LiFeSO4F, etc.

Bond-valence Based Computational Design of High Performance Lithium Ion Battery Cathode Materials

ABSTRACTLinking the bond valence mismatch to the absolute energy scale, a generally applicable Morse-type force-field is developed and applied to study ion conduction in mixed conducting solids using both an energy landscape approach and molecular dynamics (MD) simulations. Exploring strategies to enhance the power performance of safe low cost lithium ion battery cathode materials, amblygonite-type “high voltage” cathode materials LiVPO4F and LiFeSO4F are used as examples. The amblygonite-type structure exhibits channels for low-energy migration in combination with moderate energy thresholds for "back-up" pathways in perpendicular directions mitigating the effects of channel blocking in mixed conductors with strictly one-dimensional Li+ motion.

Plenary Address- New Types of Rechargeable Lithium and Lithium-Ion Polymer Batteries

The activities in progress in our laboratory for the development of new types of lithium batteries to be proposed for portable electronics and hybrid car application, are reviewed and discussed. The research has been mainly focused on the characterization of new electrode and electrolyte materials. Results related to improved, solvent-free , as well as gel-type, polymer electrolytes are particularly stressed. It is shown that the use of proper gel electrolytes in combination with suitable electrode couples, allows the development of new types of safe, reliable and low cost lithium ion batteries which appear very promising power sources for hybrid vehicles.

Power sources for portable electronics and hybrid cars: lithium batteries and fuel cells

The activities in progress in our laboratory for the development of batteries and fuel cells for portable electronics and hybrid car applications are reviewed and discussed. In the case of lithium batteries, the research has been mainly focused on the characterization of new electrode and electrolyte materials. Results related to disordered carbon anodes and improved, solvent-free, as well as gel-type, polymer electrolytes are particularly stressed. It is shown that the use of proper gel electrolytes, in combination with suitable electrode couples, allows the development of new types of safe, reliable, and low-cost lithium ion batteries which appear to be very promising power sources for hybrid vehicles. Some of the technologies proven to be successful in the lithium battery area are readapted for use in fuel cells. In particular, this approach has been followed for the preparation of low-cost and stable protonic membranes to be proposed as an alternative to the expensive, perfluorosulfonic membranes presently used in polymer electrolyte membrane fuel cells (PEMFCs).

Cycling performance of low-cost lithium ion batteries with natural graphite and LiFePO 4

Low-cost lithium ion batteries with LiFePO 4 and natural graphite were cycled in 1 M LiBF 4+EC/DEC at 100% depth of discharge and 25 °C in order to investigate cycle performance and diagnostics for capacity fading. The 12 cm 2 pouch cell showed 65% of capacity retention at 5 C compared to that at C/25. The cell showed 80% of initial capacity after 80 cycles and its capacity fade rate was 11.3 μA h/cycle during constant C/2 cycling. In hybrid pulse power characterization, the discharge resistance of this cell was higher than commercial graphite/LiCoO 2 cell because of low lithium diffusivity in LiFePO 4. Slow rate cycling in pouch full cell showed almost 40% of capacity fade after 100 cycles. However, the 100-cycled cathode and anode did not show any capacity fading in half-cell test after disassembling full cell, suggesting that capacity fade in the full cell is caused by loss of cycleable Li.