The progressive improvement of lithium-ion batteries (LIBs) leads to subsequent electrolyte design and electrode modification processes. The spinel lithium nickel manganese oxide (LiNi0.5Mn1.5O4, LNMO) is one of the potential candidates for the next generation of LIBs applied for electric vehicles due to its high working potential (4.75 V vs. Li+/Li), reasonable price, and environmental friendliness. Nevertheless, the degradation of cycling performance at high potential induces massive challenges for LNMO-based batteries commercialization. This study investigated the impact of Succinonitrile (SN) and electrode processing to strengthen and maximize the LNMO electrode and graphite||LNMO full-cell performance. According to the performance in half-cell, the sample contained 85 wt.% LNMO: 7.5 wt.% C65: 7.5 wt.% PVDF/NMP combining with the electrolyte 1.5 M LiPF6 in EC: EMC: DMC (2:1:7 – v/v) at 0.5 wt.% SN seems to be the optimal condition for further full-cell. Indeed, the promising full-cell with N/P=1.3 displays a remarkable initial capacity of 118.75 mAh.g-1 with a Coulombic efficiency of 91.64%. Moreover, it maintains a capacity retention of around 58% at the current density of 0.1C after 100 cycles.

Nowadays, a hybrid composite SiO2/C has been paid attention to improving battery performance in Li-ion batteries (LIBs) as the anode. However, this material unexpectedly suffers from initial active lithium loss caused by the solid electrolyte interface (SEI) formation leading to low initial Coulombic efficiency and significantly reducing the initial capacity. In order to solve these issues, pre-lithiation has been considered an effective approach to limit active lithium loss and increase cycling performance. This work focuses on the two most common techniques, including the direct contact method (CM) and the electrochemical method in half-cell (EM). After the pre-lithiation process, the anodes would be evaluated in full-cell with LiNi0.6Mn0.2Co0.2O2 (NMC622) cathode. According to electrochemical properties evaluations, pre-lithiation could enhance discharged capacity and initial coulombic efficiency. Without the pre-lithiation method, the discharged capacity in full-cell only witnessed 66.9 mAh.g-1, while CM and EM methods illustrated a better battery performance. In detail, EM exhibited a higher discharged capacity and initial coulombic efficiency (137.06 mAh.g-1 and 99.08%, respectively) compared to CM (99.08 mAh.g-1 and 93.23%) method. Besides, the capacity retention using EM achieved 71.4% and the discharged capacity illustrated 97.87 mAh.g-1 after 100 cycles, which is better than using CM, which only showed 71.40 mAh.g-1.

This work elucidated the structure and electrochemical performance of the layered cathode material Na xMn 0.5Co 0.5O 2 (NMC) with x~1 calcined at 650, 800 and 900 oC. XRD diffraction indicated that the NMC material possessed a phase transition from P3- to P2-type layered structure with bi-phasic P3/P2 at medium temperature. The sodium storage performance was evaluated by constant current charging/discharging. Specifically, P2-NMC exhibits the highest initial capacity of 156.9 mAh.g -1 with capacity retention of 76.2% after 100 cycles, which is superior to the initial discharge capacity is only 149.3 mAh.g -1 and severe capacity fading per cycle of P3-NMC, indicating high robust structure stability by calcined at the higher temperature. Additionally, the best performance of P2-NMC also demonstrated by the high-rate capability that delivered a capacity of 50 mAh.g -1 at charge/discharge rate up to 10C. The sodium diffusion coefficient of Na + ions into the P2-type layered structure obtained by Cyclic Voltammetry (CV) was in the range of 10 −13–10 −12 cm 2.s −1, which is inferior to the others. However, the structure stability of P2 phase contributed to the best prerformance in sodium-ion half-cell.