Characterization of Aluminum Doped Lithium-Manganese Rich Composites for Higher Rate Lithium-Ion Cathodes

Abstract

The effect of synthesis method and aluminum doping on layered lithium-manganese rich, mixed metal oxides is presented. Coprecipitation and sol-gel synthesized lithium-manganese rich composite materials revealed differences in capacity and cycle life, which appears from X-ray photoelectron spectra to be strongly related to the particles' surface reactivity. Small amounts of aluminum doping to the sol-gel material were shown to improve the rate capability and cyclability, in addition to decreasing voltage fade, as shown by differential capacity plots. The electrochemistry of an aluminum doped material was revealed to be highly dependent on the degree of aluminum doping -with the behavior of 1% doped material giving a maximum capacity of 201 mAh g −1 at 150 mAg −1 and a capacity retention of 88% after 200 cycles. The increasing energy consumption of modern societies has created a considerable demand for better approaches to not only the production and management of energy, but also its storage. Due to their high energy density and good specific energies lithium-ion batteries are attractive candidates for use in many applications such as portable devices, though there is considerable impetus for further improvement.One potentially attractive family of cathode materials are layered lithium-manganese rich, mixed metal oxides (LMR-MMO materials), of the form xLi 2 MnO 3 :(1-x)LiMO 2 (where 0 < x < 1, and M represents transition metals such as cobalt, manganese and/or nickel). Their high capacities (at low cycling rates in excess of 220 mAh g −1 at room temperature and 300 mAh g −1 at 60 • C) have generated considerable interest.1-6 However, there are still significant challenges to overcome -chiefly the material exhibits power loss due to voltage fade on cycling. 1,7,8 Furthermore, whilst properties such as capacity and cyclability are self-evidently of considerable importance, many applications require rapid access to stored energy and fast recharge times. Consequently, developing materials capable of operating at high rates is potentially quite significant.From previous studies it is clear that the electrochemical and physical properties vary depending on the material's constituent elements, stoichiometry and method of synthesis. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Given the importance of both the particle bulk and the surface to the behavior of these materials, 17,18 understanding in what way the synthetic route affects these properties is of considerable importance -particularly if careful choice and optimisation of synthetic route may mitigate voltage fade.Another possible approach to decreasing voltage fade and improving rate capability would be to dope the lithium-manganese rich material. While investigations into using chromium 19,20 and ruthenium 21 have been carried out, one potentially particularly attractive dopant is comparatively inexpensive aluminum. A computational study 22 has suggested that a small degree of aluminum doping should have a stabilizing effect on the structure, resulti...

Surface modification of Li(Li0.17Ni0.2Co0.05Mn0.58)O2 with LiAlSiO4 fast ion conductor as cathode material for Li-ion batteries

“…It is a daunting challenge for people to conquer the above mentioned problems of the Li-rich layered oxides to keep pace with the rapidly increasing requirement for satisfying batteries. Recently, people have made great efforts including cation and anion doping [10,12,13], surface modification [9,11,[14][15][16][17][18][19][20][21], innovation of synthesis method [22,23], and fabrication of nano-sized particles [6,24,25], to achieve the goal of commercialization of the Li-rich layered cathode materials. In particular, the surface modification by coating some materials such as metal oxides [15][16][17], phosphates [18][19][20], fluorides [9,11,21] has been regarded as one of the most effective measures to overcome drawbacks of Li-rich layered oxides.…”

Aluminum-based materials for advanced battery systems

“…Second, the lithium-rich material has poor rate performance and low discharge voltage plateaus during cycling, especially under high temperature [137,138]. Metal ion doping exerts an enormous function on improving the electrochemical performance of these cathode materials [139][140][141] , etc. [147][148][149][150][151][152] can facilitate the diffusion of Li ions in the material.…”

Heat Treatment Effect in the Corrosion Resistance of the Al-Co-Mn Alloys Immersed in 3 M KOH

“…One of these alternatives are the metal air batteries which in the last years are under attention due to their high energy density and capacity on load and temperature [1,2]. Based on the latter, aluminum-based alloys as air battery doped with some metal ions had been reported by different authors with metals such as Al 3+, Mg 2+ , Ti 4+ , Cr 3+ , Zn 2+ , Co 3+ , Ga 3+ , and Ti 4+ [3][4][5], due mainly to their electrical and chemical properties, as well as to their low-cost acquisition compared with other metals like lithium and zinc [4]. Some authors had reported that the major problems that this kind of batteries present are their high corrosion rate and their high hydrogen evolution when in contact with the electrolyte conducing to a low anodic efficiency [6] Electrochemical techniques such as polarization curves, cyclic voltammetry, and electrochemical impedance spectroscopy had been employed to evaluate its properties with the aim to improve its physical and chemical features [7,8].…”