Improving Thermodynamic Stability of nano-LiMn₂O₄ for Li-Ion Battery Cathode

Abstract

Nanomaterials can exhibit improved electrochemical performance in cathode applications, but their inherently high surface areas cause unconventional instability, leading to capacity fading after a limited number of battery cycles. This is because of their high surface reactivity, which makes them more susceptible to phenomena such as grain growth, sintering, solubilization, and phase transformations. Thermodynamically, these can be attributed to an increased contribution of interfacial enthalpies to the total free energy of the system. The lack of experimental data on the interfacial thermodynamics of lithium-based materials has hindered strategies to mitigate such degradation mechanisms. In this study, interfacial energies of LiMn2O4 nanoparticles were directly measured for the first time using calorimetry, and the possibility of thermodynamically manipulating both surface and grain boundary energies using a dopant (scandium) was explored. We show that undoped LiMn2O4 nanoparticles have a surface energy of 0.85 J/m2, which is significantly lower than that of LiCoO2. Moreover, introducing scandium further lowered the LiMn2O4 surface energy, leading to a demonstrated improved stability against coarsening and reactivity to water, which can potentially result in more stable cathode materials for battery applications.

Nano and Battery Anode: A Review

“…In addition to one-dimensional nanostructures (nanowires and nanotubes), efforts have been made to use zero-dimensional nanostructures (nanoparticles) (as a good nanoparticle are easier to synthesize than nanowires). The problem with nanoparticles is that on the one hand it is not possible to easily make a connection between the nanoparticles themselves and on the other hand between them and the conductive and collecting material [ 32 , 35 , 36 ]. For example, Fig.…”

“…In nanowires, electron transfer (communication between the current collector and the active substance) takes place through the length of the nanowires. Since the electron transfer is good, the full capacity of the silicon active material can be used [31,32,[35][36][37]. Nanowires have a higher electrolyte bond season than bulk material [41][42][43].…”

“…4 Charging and discharging diagram for 10-micron silicon particles [17] Fig. 5 TEM image of silicon nanoparticles during lithium ionization progressed from a to h it lithium ionization, respectively [19] to easily make a connection between the nanoparticles themselves and on the other hand between them and the conductive and collecting material [32,35,36]. For example, Fig.…”

“…Metal oxides (Fe 2 O 3 , Fe 3 O 4 , CoO, Co 3 O 4 , MnxOy, Cu 2 O/CuO, NiO, Cr 2 O3, RuO 2 , MoO 2 /MoO 3 etc.) 500–1200 High capacity High energy Low cost Environmentally compatibility High specific capacity Low operation potential and Low polarization than counter oxides Low coulumbic efficiency Unstable SEI formation Large potential hysteresis Poor cycle life Poor capacity retention Short cycle life High cost of production [ 32 , 33 , 35 – 38 ] Conversion materials b. Metal phoshides/sulfides/nitrides (MXy; M ¼ Fe, Mn, Ni, Cu, Co etc.…”

“…To solve this problem, they provide LTO nanostructures. Because this anode did not have SEI from the beginning, when it becomes Nano, it does not have the problem of forming more SEI, so it does not have more nanomaterial activity [ 32 , 35 – 37 ].…”