Sacrificial Prelithiation Using Different Lithium Salt-Coated LNMO Cathodes for Stabilizing the Electrode Structure and Enhancing Battery Performance

The cobalt-free, high-voltage spinel-type cathode LiNi_0.5Mn_1.5O₄ (LNMO) exhibits high energy and power densities, rendering it a promising candidate for incorporation into next-generation lithium-ion batteries (LIBs). However, its high operating voltage of 4.7 V can lead to electrolyte decomposition, causing structural damage. In addition, the irreversible loss of active lithium in the early cycles reduces capacity performance, hindering its commercial application. To take full advantage of the catalytic effect of LNMO and the prelithiation of sacrificial salt, this work involved blending sacrificial salts (Li₂C₂O₄, Li₂CO₃, and CH₃COOLi) with LNMO to form prelithiated electrodes (LNMO-Sac) and investigating the influence of different sacrificial salts on the performance of LIBs. The results demonstrate that LNMO could efficiently catalyze the decomposition of sacrificial salts and promote the formation of a more stable electrode-electrolyte interface after cycling to mitigate structure destruction of electrodes caused by electrolyte decomposition. Compared with other sacrificial salts, Li₂C₂O₄ provided a highly efficient supplement of active lithium and improved the electrochemical performance of the battery. Thus, LNMO-Li₂C₂O₄ achieved an excellent discharge capacity of 137.9 mAh g^-1 at 1C, and capacity retention of 85.9% after 500 cycles, superior to that of LNMO without prelithiation. Moreover, the LNMO-LO/Gr full cell presented an initial capacity of 117.9 mAh g^-1 and retained 79.4 mAh g^-1 after 300 cycles. This work demonstrates the feasibility of a sacrificial salt as a lithium replenishment strategy for LNMO in practical applications.