Enhanced Stability of Cobalt-Free Spinel LiMn1.5Ni0.5O4 with V Doping for High-Voltage Li-Ion Batteries in Organic and Ionic Liquid Electrolytes
High-voltage spinel cathode material LiMn<inf>1.5</inf>Ni<inf>0.5</inf>O<inf>4</inf> (LMNO) has attracted great interest due to its large theoretical capacity, energy density and cobalt-free chemistry. However, high voltage cycling leads to accelerated decompositi...
| Authors: | , , , , , , , , |
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| Format: | article |
| Status: | Versión enviada para evaluación y publicación |
| Publication Date: | 2025 |
| Country: | España |
| Institution: | Basque Center for Applied Mathematics (BCAM) |
| Repository: | BIRD. BCAM's Institutional Repository Data |
| OAI Identifier: | oai:bird.bcamath.org:20.500.11824/2070 |
| Online Access: | http://hdl.handle.net/20.500.11824/2070 https://doi.org/10.1016/j.jallcom.2025.183060 |
| Access Level: | Embargoed access |
| Keyword: | Li-ion batteries High-voltage spinel cathode materials V-doping Ionic liquid and organic electrolytes DFT ML molecular dynamics |
| Summary: | High-voltage spinel cathode material LiMn<inf>1.5</inf>Ni<inf>0.5</inf>O<inf>4</inf> (LMNO) has attracted great interest due to its large theoretical capacity, energy density and cobalt-free chemistry. However, high voltage cycling leads to accelerated decomposition of organic electrolytes (OEs) and to capacity fading in TFSI-based ionic liquid (IL) electrolytes. To address these challenges, LMNO nanorod particles were synthesized based on α-MnOOH nanorod templates, facilitating the co-precipitation of lithium and nickel cations. Several vanadium dopant contents were subsequently explored (LiMn<inf>1.5-x</inf>Ni<inf>0.5</inf>V<inf>x</inf>O<inf>4</inf>, where x = 0.01, 0.03, and 0.05), resulting in spinel structures with enhanced structural and electrochemical stability in both OEs and ILs. Morphological and compositional analyses highlighted the reduction of Mn<sup>4 +</sup> to Mn<sup>3+</sup> to sustain electroneutrality within the lattice, as well as the coexistence of two cubic spinel phases (disordered Fd3̅m and ordered P4<inf>3</inf>32) in contributing to superior electrochemical performance and stability. Moreover, the rod-like particle morphology displayed a high-rate capability comparable to that of the well-known octahedral morphology. Density Functional Theory (DFT) calculations confirmed that increasing V-content promotes the formation of the Fd3̅m spinel phase, while incorporation of V in ordered P4<inf>3</inf>32 is not energetically favourable. In addition, machine learning-based molecular dynamics (MD) simulations showed that increasing V-content tends to decrease Li-ion diffusion barriers, increasing the intrinsic ionic mobility in the cathode. Remarkably, LiMn<inf>1.49</inf>Ni<inf>0.5</inf>V<inf>0.01</inf>O<inf>4</inf> demonstrated excellent capacity retention when cycled in an OE (75.11 % in LMNO vs 84.33 % in V-doped LMNO) and in IL electrolyte (30.79 % in LMNO vs 79.33 % for V-doped LMNO), positioning it as a promising and safer candidate high-voltage cathode. |
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