Intelligent phase-transition MnO₂ single-crystal shell enabling a high-capacity Li-rich layered cathode in Li-ion batteries

Abstract

A MnO2 single-crystal shell is synthesized on the surface of Li-rich Mn-based materials, enabling high-capacity Li-rich layered cathode in Li-ion batteries.

In Situ Reconstruction of the Spinel Interface on a Li-Rich Layered Cathode Material with Enhanced Electrochemical Performances through HEPES and Heat Treatment Strategy

“…The large Li + diffusion channel of the modified LLO material could help to improve the rate performance of LLO electrodes. 24 The minor difference in the lattice parameters of these materials suggests that the HEPES treatment did not change the overall structure of the materials. 25 The experimental Brunauer−Emmett−Teller (BET) values of the pristine LLO, 10%HEPES-LLO-H 2 , 10%HEPES-LLO-Ar, and 10%HEPES-LLO-Air samples are 2.4552, 7.4445, 8.4461, and 8.8552 m 2 g −1 , respectively (Table 1).…”

“…The large Li + diffusion channel of the modified LLO material could help to improve the rate performance of LLO electrodes . The minor difference in the lattice parameters of these materials suggests that the HEPES treatment did not change the overall structure of the materials .…”

Oxygen-deficient TiO2−x interlayer enabling Li-rich Mn-based layered oxide cathodes with enhanced reversible capacity and cyclability

“…57 The LMLO cathode with the TiO 2−x -coated separator had a smaller angle shi of the (003) and ( 104) diffraction peaks at the end of discharge than the LMLO cathode with the Celgard 2400 separator due to the improved reversibility during the rst charge and discharge. 61 To understand the inuence of the TiO 2−x interlayer on the structural evolution of the LMLO cathode during the cycling process, the coin cells aer 100 cycles were disassembled to compare the XRD patterns of the LMLO cathode with the Celgard 2400 separator and that with the TiO 2−x -coated separator. As shown in Fig.…”

Origin and characterization of the oxygen loss phenomenon in the layered oxide cathodes of Li-ion batteries

“…For instance, XAS and XPS techniques revealed that the side reaction between the cathode and the electrolyte enhanced the oxygen loss from the cathode structure. 101,107–109 Noked et al coated an alkylated Li x Si y O z layer onto a Li-rich layered oxide cathode, inhibiting the reaction and reducing the oxygen release during the operation, resulting in a better capacity retention of 81.4% after 200 cycles at a cycling rate of C/3. 175 Cho et al synthesised a stable spinel Li-Mn–O shell outside the layered Ni-rich cathode, showing a high reversible capacity of 200 mA h g −1 and 95% capacity retention under severe test conditions of 60 °C.…”

“…72,[105][106][107] During cycling, the inevitable exothermic side reaction and electrochemical process could release heat and elevate the temperature inside the cell, which leads to the phase transition of LLMO cathodes. 10,108 For example, Ni-rich NCM cathode particles were observed to reconstruct at high temperatures and transit to a rock-salt-like structure during heating (Fig. 4a and b).…”