Unveiling the Fabrication of "Rocking-Chair" Type 3.2 and 1.2 V Class Cells Using Spinel LiNi_0.5Mn_1.5O₄ as Cathode with Li₄Ti₅O₁₂

We first report the possibility of using spinel LiNi_0.5Mn_1.5O₄ (LNM) nanofibers as cathode for constructing high (∼3.2 V) and low (∼1.2 V) voltage "rocking-chair" type Li-ion cells with spinel Li₄Ti₅O₁₂ (LTO) by utilizing Li-insertion into tetrahedral (Ni^2+/4+) and octahedral (Mn^4+/3+) sites of LNM. We also explored the possibility of constructing symmetric cells (LNM/LNM) with a working potential of ∼1.8 V. Among the three configurations investigated, LNM/LTO (electrochemically prelithiated) is found superior in terms of high rate capability, cyclability, and good capacity retention characteristics. High performance spinel LNM nanofibers are prepared via a scalable electrospinning technique and their Li-insertion properties are evaluated in half-cell assembly. The half-cell studies are used for adjusting the mass balance while fabricating "rocking-chair" Li-ion cells.