Implications of the first cycle irreversible capacity on cell balancing for Li2MnO3–LiMO2 (M=Ni, Mn, Co) Li-ion cathodes

In situ Raman spectroscopy of layered solid solution Li2MnO3–LiMO2 (M = Ni, Mn, Co)

“…However charging this material above 4.5 V can apparently electrochemically activate the material due to the extraction of Li and O, which in turn leads to the formation of the MnO 2 host structure in the compound which can then reversibly intercalate lithium ions [9]. One of the drawbacks with such materials is their high irreversible capacity, which has been focus of research in many scientific groups [10,11]. Various mechanisms have been given for the explanation of the first cycle charge profile behavior in these electrode system using different characterization tools.…”

“…Experiments have been carried out to quantify the amount of utilizable lithium that is made available for the corresponding anodes when employing Li 2 MnO 3 eLiMO 2 as cathodes. It has been shown that almost none of the cathode irreversible charge capacity resulted in lithiation of the anode, demonstrating that lithium released from the cathode (and made available at the anode) during the first charge is not proportionate to the cathode charge capacity [11]. Another detailed study on Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 has been reported by Yabuuchi et al and it has been shown that some of the capacity in such kind of electrode materials is due to the electrochemical redox reaction of the oxygen molecules at the surface of the electrode [17].…”

Aluminum Borate Coating on High-Voltage Cathodes for Li-Ion Batteries

“…Li-rich layered-layered cathode materials of the form Li 2 MnO 3 -LiMO 2 (M = Mn, Co, Ni) [1][2][3][4] have attracted considerable interest over the last decade due to their higher specific capacities (240-280 mAh/g) compared to the state of art cathode materials such as LiMn 2 5 However, these high capacity materials have yet to be adopted in commercial cells due to multiple technical barriers, including voltage and power fade during cycling, poor power characteristics, and modest cycle life at the high charging voltage (>4.5 V) necessary to achieve these capacities. A unique feature of these layered-layered NMC (LLNMC) cathode materials is that they release oxygen during the first charge step at 4.5 V, 2,[6][7][8] concomitant with oxidation of the Li 2 MnO 3 component. Although this process enables the material to yield its high specific capacity, the resulting structural instability and degradation, oxygen-induced reactions, and loss of lithium to oxidation products cause an irreversible capacity loss of 50-100 mAh/g during the formation cycle.…”

Influence of cobalt content on the electrochemical properties of sheet-like 0.5Li2MnO3·0.5LiNi1/3+xCo1/3−2xMn1/3+xO2 as lithium ion battery cathodes

“…[1][2][3][4] The most attractive merit of 0.5Li 2 MnO 3 ?0.5LiNi 1/3+x Co 1/322x Mn 1/3+x O 2 is their high reversible capacities (200-300 mAh g 21 ); nevertheless, the initial activation of Li 2 MnO 3 component will lead to a high irreversible capacity loss and give a low coulombic efficiency. [3][4][5][6][7][8][9][10][11][12][13][14][15][16] Herein, for the assembled model half-cells of 0.5Li 2 MnO 3 ?0.5LiNi 1/3+x Co 1/322x Mn 1/3+x O 2 /Li within the electrochemical window of 2.0 and 4.7 V (vs. Li + /Li), the initial voltage profiles of as-prepared sheet-like superstructures are representatively shown in Fig. 3 g 21 with a coulombic efficiency of 83.0%, 82.1%, 81.3%, 76.7% or 80.3%, respectively.…”

“…(1 2 y)LiMO 2 electrodes are charged to 4.6 V or higher, the inert component Li 2 MnO 3 can be activated and be simultaneously transformed into another active component MnO 2 . [6][7][8][9][10][11][12][13] By considering the structural and thermal stability of an integral solid solution, the molar ratio between solute and solvent is usually preset at an appropriate value of 1 : 1 (i.e., y = 0.5) for the material preparation of yLi 2 MnO 3 ? (1 2 y)LiMO 2 .…”