Preparation of Spheroidal Spinel LiMn₂O₄ and Its High Temperature Performance

Abstract

In view of the high temperature instability of spinel LiMn 2 O 4 , a combination of elemental doping, material coating and morphology controlling was designed to improve its high temperature performance in this paper. The spherical MnO 2 intermediate was prepared by the action of organic polyvinylpyrrolidone and ethylene glycol. Then, under the coating and doping of graphene and Al, a spheroidal LiMn 2 O 4 material was obtained. The obtained materials were characterized by XRD, SEM, particle size analysis and electrochemical performance test. The results show that the introduction of graphene and Al can reduce the unit cell volume of LiMn 2 O 4 , shorten the interplanar spacing of each crystal plane, improve the stability of the unit cell and maintain its spherical structure. Amongst which, Al doping can greatly reduce the particle size. The electrochemical performance test at 55°C shows that simultaneous Al doping and graphene coating can not only maintain the spheroidal structure of LiMn 2 O 4 cathode material, but also make it have good electrochemical properties: the initial discharge capacity can be up to 123.4 mAh.g −1 at 0.2 C rate and there is a discharge capacity of 101.2 mAh g −1 after 100 cycles. The sample with only graphene coating has a capacity of 91.7 mAh.g −1 after 100 cycles, while the sample without Al doping and graphene coating has a capacity of only 22.4 mAh.g −1 after 100 cycles.

Facile and efficient recycling of cathode materials of spent lithium manganate batteries

“…Interestingly, the leaching behavior of the LMOs in this recycling process is similar to that of LMO cathode materials during battery charging. 28,29…”

“…Interestingly, the leaching behavior of the LMOs in this recycling process is similar to that of LMO cathode materials during battery charging. 28,29 Fig. 3(b) shows the FT-IR spectra of the products of the spent LMOs at different leaching efficiencies.…”

Effects of Lithium Salt Addition Methods on the High-Temperature Electrochemical Performance of LiMn2O4

“…10 Our group has previously reported that graphene (G) coating can be used to reduce the corrosion of electrolyte on LiMn 2 O 4 materials and aluminum doping can be used to suppress Jahn-Teller effect. 11 Combining the action of G coating and aluminum doping, using the inducing effect of the spherical MnO 2 intermediate, a spherical LiMn 2 O 4 cathode material with good high-temperature performance can be prepared through a traditional solid-phase method. 11 In further follow-up research, we found that in addition to element doping and material coating, the way of lithium salt addition would also affect the high-temperature performance of the LiMn 2 O 4 cathode materials.…”

“…11 Combining the action of G coating and aluminum doping, using the inducing effect of the spherical MnO 2 intermediate, a spherical LiMn 2 O 4 cathode material with good high-temperature performance can be prepared through a traditional solid-phase method. 11 In further follow-up research, we found that in addition to element doping and material coating, the way of lithium salt addition would also affect the high-temperature performance of the LiMn 2 O 4 cathode materials. A suitable way of adding lithium salt can not only improve its high-temperature performance, but also effectively shorten its calcination time.…”

“…ExperimentalPreparation of MnO 2 intermediate.-MnSO 4 .H 2 O and NH 4 HCO 3 were used as raw materials, polyvinylpyrrolidone (PVP) and ethylene glycol were added as templating agents, and MnO 2 intermediates were obtained by precipitation and heat treatment 11. Amongst which, MnO 2 prepared by adding G and aluminum powder during the preparation process was named as G-Al-M, while MnO 2 prepared without G and aluminum powder was named as M.…”