Hooked on switch: strain-managed cooperative Jahn–Teller effect in Li_0.95Mn_2.05O₄ spinel

Abstract

Compression and heating of Li0.95Mn2.05O4 induce a unique three-way switch. We demonstrate the possibility of tuning of the structural properties and the induction of phase transitions by changing the external pressure and temperature, and hence changing the lattice strain.

Unveiling the Reaction Mechanism during Li Uptake and Release of Nanosized “NiFeMnO4”: Operando X-ray Absorption, X-ray Diffraction, and Pair Distribution Function Investigations

“…The occurrence of alternating spinel and rock salt domains in solid solutions of rock salt and spinel samples was discussed by Armbruster . In addition, rock salt and defect rock salt-type impurities, i.e., NiO, Ni 0.5 Mn 0.5 O, or Ni 6 MnO 8 , were reported several times in these and closely related compounds. ,− Nevertheless, due to the uniform cation distribution, revealed by TEM-energy-dispersive X-ray (EDX) mapping analysis, it can be assumed that a domain intergrowth as described in ref is more likely than a phase separation.…”

“…Larson et al proposed a critical concentration of Mn 3+ of 58–65% above which a tetragonal symmetry reduction occurs. 29,33−35 This value can be reduced by substituting of Fe 3+ for Mn 3+ . The first report about NiMnFeO 4 nanoparticles (<100 nm) as anode material showed a reversible capacity of 750 mAh/g after 50 cycles, comparable to the performance of NiFe 2 O 4 and even better than that of NiMn 2 O 4 .…”

“…Moreover, due to an appreciable amount of the Jahn–Teller ion Mn 3+ on the B site, Mn 3+ containing spinels often exhibit a tetragonal distortion and the symmetry is reduced ( Fd 3̅ m → I 4 1 / amd ). Larson et al proposed a critical concentration of Mn 3+ of 58–65% above which a tetragonal symmetry reduction occurs. ,− This value can be reduced by substituting of Fe 3+ for Mn 3+ . The first report about NiMnFeO 4 nanoparticles (<100 nm) as anode material showed a reversible capacity of 750 mAh/g after 50 cycles, comparable to the performance of NiFe 2 O 4 and even better than that of NiMn 2 O 4 …”

Alginic acid-derived mesoporous carbon (Starbon®) as template and reducing agent for the hydrothermal synthesis of mesoporous LiMn2O4 grafted with carbonaceous species

“…[1][2][3][4][5][6] However, practical implementation of LMO technology is hampered by a low rate capability and fading of its capacity during cycling, mainly due to the dissolution of manganese in the electrolyte [7][8][9] and to the phase transition from the cubic spinel to a tetragonal crystal structure caused by Jahn-Teller distortion. 10,11 Over the years, many efforts have been made to address these problems, including doping, [12][13][14] carbon coating, 15,16 and nanostructuring of LMO. [17][18][19][20][21][22] Nano-structuration leading to mesoporous LMO materials has been shown to enhance the battery performance, due to the large surface area favoring better interfacial contact between electrode and electrolyte, [23][24][25][26][27] and to the fast lithium ion diffusion through the mesopores.…”

Research progress on design strategies, synthesis and performance of LiMn2O4-based cathodes

“…12,13 Despite the above-mentioned advantages, fast capacity fading during cycling at high temperature, which is due to such possible factors as manganese dissolution, and Jahn-Teller distortion, etc., seriously limits such materials' practical life span. [14][15][16][17] As a semiconductor, LiMn 2 O 4 has a band gap of 1.3 eV and low electrical conductivity ($10 À6 S cm À1 ), which leads to an inferior rate capability. 18 Some research has been done on the electrochemical behavior and degradation mechanism in Li-ion batteries.…”