Li-ion battery materials: present and future

Metal Oxides and Oxysalts as Anode Materials for Li Ion Batteries

Research to develop alternative electrode materials with high energy densities in Li-ion batteries has been actively pursued to satisfy the power demands for electronic devices and hybrid electric vehicles. This critical review focuses on anode materials composed of Group IV and V elements with their composites including Ag and Mg metals as well as transition metal oxides which have been intensively investigated. This critical review is devoted mainly to their electrochemical performances and reaction mechanisms (313 references).

Li-alloy based anode materials for Li secondary batteries.

Recent developments in cathode materials for lithium ion batteries

For more than 20 years, most of the technological achievements for the realization of positive electrodes for practical rechargeable Li battery systems have been devoted to transition metal oxides such as LixMO2 (M = Co, Ni, Mn), LixMn2O4, LixV2O5, or LixV3O8. The first two classes of materials built on close-packed oxygen stacking adopt bidimensional and tridimensional crystal structures, respectively (Figure 1), from which lithium ions may be easily intercalated or extracted in a reversible manner. These oxides are reasonably good ionic and electronic conductors, and lithium insertion/extraction proceeds while operating on the M4+/M3+ redox couple, located between 4 and 5 V versus Li+/Li...

Polyanionic (phosphates, silicates, sulfates) frameworks as electrode materials for rechargeable Li (or Na) batteries.

Lithium has been inserted into the spinel Li4Ti5O12 by both chemical and electrochemical methods. The cation distribution in the lithiated phases has been analyzed by 6,7Li NMR, Raman spectroscopy, and X-ray diffraction, and the distribution in the chemically inserted compound has been analyzed additionally by neutron diffraction. A refinement of structural parameters has been carried out by applying the Rietveld method to the neutron diffraction pattern. It is shown that the two insertion methods are based on different mechanisms. Chemically inserted lithium ions are trapped in the (48f) sites of the spinel structure from which they cannot be extracted by electrochemical means. In contrast to the electrochemical Li-insertion, which is accompanied by a spinel to rocksalt phase transition, no such structural change is found for chemical insertion. The consequences of the two different mechanisms for the reversibility of the insertion process are discussed.

Chemical and Electrochemical Li-Insertion into the Li4Ti5O12 Spinel

A LiCoPO 4 cathode material with, to our knowledge the highest discharge capacity (125 mAh/g) is reported. The phosphate is obtained by using a novel solid-state synthesis procedure. The basic idea of the novel synthesis procedure is the use of an alternative cobalt-containing precursor (CoNH 4 PO 4 ) and a lithium excess synthesis with carbon black as temporal dispersing agent, later eliminated as CO 2 . The carbon black addition produces lower average particle size than conventional preparations, yielding a finely dispersed solid. The low particle size is responsible for a better electrochemical behavior. Finally the effects of scan rate and potential window on the electrochemical performance are discussed.

Improvement of the Electrochemical Performance of LiCoPO4 5 V Material Using a Novel Synthesis Procedure

Structural and comparative electrochemical study of M(II) oxalates, M = Mn, Fe, Co, Ni, Cu, Zn

SnO reduction in lithium cells: study by X-ray absorption, 119Sn Mössbauer spectroscopy and X-ray diffraction

Spinel oxides with LiM x Mn 2 - x O 4 (M = Fe, Ni) formula are known to be interesting electrode materials for lithium-ion batteries. These materials show a significant near 5 V capacity, which results from changes in the oxidation state of the transition metal M. In this work, compounds of the LiNi 0 . 5 - y Fe y Mn 1 . 5 O 4 series have been characterized. The charge/discharge curves of lithium test cells using these compounds as active electrode material show two plateaus. The first one, below 4.5 V, is ascribed to a Mn 4 + /Mn 3 + pair, while the second, between 4.5 and 5.1 V, can be attributed to Ni 4 + /Ni 2 + and Fe 4 + /Fe 3 + pairs. High capacity and excellent capacity retention is obtained for some compositions with intermediate y values. The suppression of the multiphase mechanism of insertion-deinsertion commonly found for LiNi 0 . 5 Mn 1 . 5 O 4 by iron substitution is evidenced for compositions in the 0 < y ≤ 1 range. The change in mechanism is correlated with the improvement in electrochemical performance. Moreover, cation distribution, which includes the presence of iron in the tetrahedral sites of the spinel structure, stabilizes the solid upon prolonged cycling.

C. Pérez Vicente

Papers

Chemical and Electrochemical Li-Insertion into the Li4Ti5O12 Spinel

Improvement of the Electrochemical Performance of LiCoPO4 5 V Material Using a Novel Synthesis Procedure

Structural and comparative electrochemical study of M(II) oxalates, M = Mn, Fe, Co, Ni, Cu, Zn

SnO reduction in lithium cells: study by X-ray absorption, 119Sn Mössbauer spectroscopy and X-ray diffraction

Synergistic Effects of Double Substitution in LiNi0.5 − y Fe y Mn1.5 O 4 Spinel as 5 V Cathode Materials