Enhanced electrochemical performance of LiMn 2 O 4 by constructing a stable Mn 2+ -rich interface

Deep‐Eutectic‐Solvent‐Based Self‐Healing Polymer Electrolyte for Safe and Long‐Life Lithium‐Metal Batteries

“…It was found that the concentration of Mn dissolved in the DSP electrolyte (0.20 ppm per mg of LMO, inset in Figure a) was significantly lower than that in the DES+FEC electrolyte (0.25 ppm; see Figure S17) and the DES electrolyte (2.31 ppm; see Figure a). Moreover, in the Mn 2p 3/2 XPS spectrum of the cycled LMO electrode DES electrolyte, three peaks appeared at around 641.1, 642.2, and 643.9 eV, which can be assigned to Mn 2+ , Mn 3+ , and Mn 4+ , respectively (Figure b) . Intriguingly, the peak intensity of Mn 2+ dramatically decreased with the introduction of the FEC additive (see Figure S18) and the UPyMA‐PETEA polymer matrix (Figure c), which is highly consistent with the ICP‐MS results.…”

“…Moreover,i nt he Mn 2p 3/2 XPS spectrum of the cycled LMO electrode DES electrolyte,three peaks appeared at around 641.1, 642.2, and 643.9 eV,w hich can be assigned to Mn 2+ ,M n 3+ ,a nd Mn 4+ , respectively (Figure 6b). [40] Intriguingly,the peak intensity of Mn 2+ dramatically decreased with the introduction of the FEC additive (see Figure S18) and the UPyMA-PETEA polymer matrix (Figure 6c), which is highly consistent with the ICP-MS results.…”

Controllable Fabrication and Li Storage Kinetics of 1 D Spinel LiMn2O4 Positive Materials for Li‐ion Batteries: An Exploration of Critical Diameter

“…This is because that in addition to the adversee ffect of the electrochemically inactive surface, the nanorods are unstable and may be easily broken after long-term cycling when the diameter is decreased to some extent, whichl eads to the poor contact between the electrode and the current collector. [47] To confirm this deduction, the XRD analysis and SEM observation for the spent electrodes of LMO-1 and LMO-2 samples were further performed to determine the changes in crystal www.chemsuschem.org structurea nd morphology.A fter 500 cycles, the coin cells for LMO-1 and LMO-2 were disassembledi naglove box and the active materials were obtained after washing and low-temperature calcination (to removet he acetylene black and polyvinylidene difluoride). Figure 7c exhibits the XRD patterns of the LMO-1 and LMO-2 after cycling, respectively.C ompared to the LMO-2,t he diffraction peaks of LMO-1 are substantially weakened and widened because of the structural change.…”

“…One unanticipated finding is that LMO‐1 with the smallest diameter exhibits the lowest Li + diffusion coefficient. This is because that in addition to the adverse effect of the electrochemically inactive surface, the nanorods are unstable and may be easily broken after long‐term cycling when the diameter is decreased to some extent, which leads to the poor contact between the electrode and the current collector …”

Fabrication of an LiMn2O4@LiMnPO4 composite cathode for improved cycling performance at high temperatures

“…LMP exhibits excellent thermal and chemical stability, which is attributed to its phosphate framework, and possesses the same working voltage as that of LMO (~4.1 V) [26]. Recently, core-shell LMO@LMP cathodes were fabricated [27,28] and exhibited good cyclability at room temperature, which is attributed to the coating [28]. However, the cycling performance of the coreshell LMO@LMP cathode and that of the non-coated LMO cathode decreased at 55°C.…”