Abstract
To reduce surface contamination and increase battery life, MoO3 nanoparticles were coated with a high-voltage (5 V) LiNi0.5Mn1.5O4 cathode material by in-situ method during the high-temperature annealing process. To avoid charging by more than 5 V, we also developed a system based on anode-limited full-cell with a negative/positive electrode (N/P) ratio of 0.9. The pristine LiNi0.5Mn1.5O4 was initially prepared by high-energy ball-mill with a solid-state reaction, followed by a precipitation reaction with a molybdenum precursor for the MoO3 coating. The typical structural and electrochemical behaviors of the materials were clearly investigated and reported. The results revealed that a sample of 2 wt.% MoO3-coated LiNi0.5Mn1.5O4 electrode exhibited an optimal electrochemical activity, indicating that the MoO3 nanoparticle coating layers considerably enhanced the high-rate charge–discharge profiles and cycle life performance of LiNi0.5Mn1.5O4 with a negligible capacity decay. The 2 wt.% MoO3-coated LiNi0.5Mn1.5O4 electrode could achieve high specific discharge capacities of 131 and 124 mAh g−1 at the rates of 1 and 10 C, respectively. In particular, the 2 wt.% MoO3-coated LiNi0.5Mn1.5O4 electrode retained its specific capacity (87 mAh g−1) of 80.1% after 500 cycles at a rate of 10 C. The Li4Ti5O12/LiNi0.5Mn1.5O4 full cell based on the electrochemical-cell (EL-cell) configuration was successfully assembled and tested, exhibiting excellent cycling retention of 93.4% at a 1 C rate for 100 cycles. The results suggest that the MoO3 nano-coating layer could effectively reduce side reactions at the interface of the LiNi0.5Mn1.5O4 cathode and the electrolyte, thus improving the electrochemical performance of the battery system.
Highlights
The results revealed that the LiNi0.5 Mn1.5 O4 (LNMO)-MoO3 -2 electrode exhibited the best electrochemical performance, with specific discharge capacities of 129, 131, 131, 127, 127, and 124 mAh g−1 at rates of 0.2, 0.5, 1, 3, 5, and 10 C, respectively
The results indicated that the LNMOMoO3 -2 electrode exhibited an initial specific discharge capacity of 109 mAh g−1, which decreased to 87 mAh g−1 after 500 cycles with a capacity retention of approximately 80.1%
Spinel LNMO cathode materials coated with MoO3 layers were successfully prepared using solid-state reactions and the wet-chemical method
Summary
Secondary electrochemical cells, such as lithium-ion batteries (LIBs), are an emerging energy storage technology, widely used in portable electronic devices, battery-powered all-electric vehicles (plug-in electric vehicles or hybrid electric vehicles), and other storage grids [1,2,3,4]. The development of high-performance cathode materials is the main bottleneck in the commercial application of LIBs. the development of high-performance cathode materials is the main bottleneck in the commercial application of LIBs Conventional cathode materials, such as LiCoO2 , LiFePO4 , and LiMn2 O4, exhibit lower energy densities because of their lower working voltages and discharge capacities [5,6]. LiNi0.5 Mn1.5 O4 (LNMO) has gained considerable attention as the next-generation cathode material in LIBs, because of Nanomaterials 2022, 12, 409.
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