Spinel LiMn2O4 Cathode Materials in Wide Voltage Window: Single-Crystalline versus Polycrystalline

Abstract

Single-crystal (SC) layered oxides as cathodes for Li-ion batteries have demonstrated better cycle stability than their polycrystalline (PC) counterparts due to the restrained intergranular cracking formation. However, there are rare reports on comparisons between single-crystal LiMn2O4 (SC-LMO) and polycrystalline LiMn2O4 (PC-LMO) spinel cathodes for Li-ion storage. In this work, the Li-ion storage properties of spinel LiMn2O4 single-crystalline and polycrystalline with similar particle sizes were investigated in a wide voltage window of 2–4.8 V vs. Li/Li+. The SC-LMO cathode exhibited a specific discharge capacity of 178 mA·h·g−1, which was a bit larger than that of the PC-LMO cathode. This is mainly because the SC-LMO cathode showed much higher specific capacity in the 3 V region (Li-ion storage at octahedral sites with cubic to tetragonal phase transition) than the PC-LMO cathode. However, unlike layered-oxide cathodes, the PC-LMO cathode displayed better cycle stability than the SC-LMO cathode. Our studies for the first time demonstrate that the phase transition-induced Mn(II) ion dissolution in the 3 V region rather than cracking formation is the limiting factor for the cycle performance of spinel LiMn2O4 in the wide voltage window.

Li–Mn Bimetallic Metal–Organic Framework and Its Derivative as a Cathode for Lithium-Ion Batteries

“…The LiMn 2 O 4 prepared via this method can exhibit higher cycle stability at a high rate than the reported LiMn 2 O 4 with ca. 67 or 48% of its original capacity after 50 cycles . The data show that the electrical properties of the materials can be improved when combined with the morphological characteristics of the sample and the XPS test results.…”

“…67 or 48% of its original capacity after 50 cycles. 35 The data show that the electrical properties of the materials can be improved when combined with the morphological characteristics of the sample and the XPS test results. Part of the reason is that the carbon was retained after calcination, which improves the conductivity of the material.…”

Ethanothermal Synthesis of Octahedral-Shaped Doped Mn2O3 Single Crystals as a Precursor for LiMn2O4 Spinel Cathodes in Lithium-Ion Batteries

“…In particular, various protocols, such as precipitation, solvothermal, sol–gel, and templating methods, have been used to form Mn 2 O 3 in various particle sizes and morphologies. − However, thus far, most of the research has focused on the synthesis that maximizes the surface area to use the pseudo-capacitance based on the faradic charge-transfer function of Mn oxide itself, , leading to synthesis efforts in various nanostructure forms. − As a result, the synthesis of micrometer-sized or larger bulk particles has not received much attention. With respect to lithium-ion batteries, the synthesis of spinel cathodes with large particle size is necessary to maximize the tap density and volumetric energy density and minimize the surface reactivity with the electrolyte and Mn dissolution. , In this regard, synthesizing cathode materials in single-crystalline form with a few micrometer size is appealing. − …”

“…With respect to lithium-ion batteries, the synthesis of spinel cathodes with large particle size is necessary to maximize the tap density and volumetric energy density and minimize the surface reactivity with the electrolyte and Mn dissolution. 22,23 In this regard, synthesizing cathode materials in single-crystalline form with a few micrometer size is appealing. 24−26 We present here the doping of various elements into Mn 2 O 3 during a solvothermal synthesis process.…”

Electrochemically Deposited MoS2 and MnS Multilayers on Nickel Substrates in Inverse Opal Structure as Supercapacitor Microelectrodes

“…Compared with the traditional nickel foam, the metallic nickel inverse opal structure has a much higher specific surface area and can replace the bulky nickel foams as the substrate of the supercapacitor cathode materials. It is worth noting that the Mn-based cathode is also distinguished by its low toxicity, plentiful supply, exceptional safety, and environmental friendliness [ 21 , 22 ], and the supercapacitor synthesis starts to combine two-dimensional material such as reduced graphene oxide to increase the conductivity and surface area of the electrodes [ 23 ]. Therefore, the active material MnS/MoS 2 was deposited into the void space of a metallic nickel inverse opal structure through an electrochemical deposition method, and the ordered porous microelectrode material MnS/MoS 2 /Ni-IOS with a high specific surface area and high specific capacitance was formed.…”