Ni-Rich Oxide LiNi_0.85Co_0.05Mn_0.1O₂ for Lithium Ion Battery: Effect of Microwave Radiation on Its Morphology and Electrochemical Property

Abstract

To illustrate the effect of microwave radiation on the morphologies and electrochemical properties electrode materials, Ni-rich oxide LiNi 0.85 Co 0.05 Mn 0.1 O 2 was identified and prepared from the corresponding precursors synthesized under different reaction conditions. The results suggest that the resultant LiNi 0.85 Co 0.05 Mn 0.1 O 2 morphology controllably depends on its corresponding synthetic method, which will affect its electrochemical property accordingly. The electrode material from microwave-assisted co-precipitation followed by a hydrothermal modification (NCM-WH) possesses a pure α-NaFeO 2 phase and regular spheroidal morphology with a proper size over 10 μm, which exhibits more excellent discharge capacity of ca. 150 mAh g -1 after 200 cycles and better capacity retention of 88.3% than those from microwave-assisted co-precipitation method (NCM-W) or normal co-precipitation method (NCM-N) only. The improved electrochemical properties are confirmed from their ordered phase structure, regular spheroidal morphology and high tap density, which results in lower Li/Ni cation mixing, faster solid-state ion diffusion, higher electrochemical reversibility and better structure stability during the long-tern cycles.

New Insight into the Role of Mn Doping on the Bulk Structure Stability and Interfacial Stability of Ni‐Rich Layered Oxide

“…The initial cycle discharge capacities of the M0.01−NCA and M0.02−NCA are 183.6 and 175 mAh g −1 following by discharge capacities of 150.9 and 133.3 mAh g −1 after 200 cycles, showing higher capacity retention of 82.2 and 76.2%, respectively. While for the higher voltage cutoff of 4.5 V, the pristine NCA, M0.01‐the pristine NCA, M0.01−NCA, and M0.02−NCA samples show capacity retention of 77.7, 86 and 83% after 100 cycles at 1 C. To illustrate the improvement of cycling performance, Figure (c) shows the cycling performance diagram compared with some of the latest reported works at 4.3 V cut‐off voltage after 100 cycles, and all the involved nickel‐rich cathode materials have similar stoichiometric ratios . It is noted that our work is comparable with them, but cycling performance needs to be improved regarding the discharge capacity.…”

“… (a) Initial charge and discharge curves of pristine and the modified electrodes under a current rate of 0.1 C between 2.5–4.3 V. Cycling performance between (b) 2.5–4.3 V and (d) 2.7–4.5 V at 1 C rate and 25 °C. (c) Cycling performance diagram compared with reported works . (e) Full pouch‐type cell cyclability of pristine and M0.01−NCA samples between 3–4.2 V at 1 C rate and 25 °C.…”

“…Figure 6 Figure 6(c) shows the cycling performance diagram compared with some of the latest reported works at 4.3 V cut-off voltage after 100 cycles, and all the involved nickel-rich cathode materials have similar stoichiometric ratios. [34][35][36][37][38] It is noted that our work is comparable with them, but cycling performance needs to be improved regarding the discharge capacity. Specially, the charge and discharge curves of the 1st, 25th, 50th, 100th, 150th, 200th cycle between 2.5 and 4.3 V for the pristine and M0.01À NCA are shown in Figure S4.…”

Rational Design of a Piezoelectric BaTiO3 Nanodot Surface‐Modified LiNi0.6Co0.2Mn0.2O2 Cathode Material for High‐Rate Lithium‐Ion Batteries

“…High-resolution Ni 2p XPS spectra of pristine NCM622 and 0.5 %-NCM622@BTO are presented in Figure 2b, which values of each peak are consistent with previous reports. [32,33] There is no obvious difference between both samples in Co 2p 2/3 (780.2 eV) and Co 2p 1/2 (795.0 eV) XPS spectra, indicating that Co element is + 3 valence state in Figure S2d. [11] The spectra of Mn in Figure S2e shows that two main peaks are indexed to Mn 2p 3/2 (642.5 eV) and Mn 2p 1/2 (654.1 eV), suggesting that Mn is predominantly at + 4 valence state.…”

Microwave-assisted Synthesis and Co, Al Co-modification of Ni-rich LiNi0.8Mn0.2O2 Materials for Li-ion Battery Electrode

“…formance 锂离子电池(LIBs)作为一种新型可移动储能 设备，在固定设备储能，智能电网，交通运输等领 域的应用已初见成效 [1][2] ，而其工作电压、能量密 度、输出功率、循环寿命和安全性能在很大程度上 由正极材料所决定 [3][4] 。 层状高镍正极材料 LiNi1-xMxO2(M 为 Co、Mn 等金属元素)，具有接近 自身理论的高比容量、较高的工作电压、相对稳定 的结构和较低的成本，高镍二、三元正极材料仍将 是今后一段时间研究的重点和热点 [5][6][7] 。 尽管研究者们不断对高镍正极材料进行研究 改进， 但材料本身仍然还存在一些需要解决的问题 [8][9][10][11] [12][13][14] 。另外，电极材料表面的 各种副反应对材料的电化学性能同样具有较为重 要的影响， 合成过程中残留在材料表面上过量的锂 在存储和制浆过程中与空气中的 CO2 和 H2O 发生 反应形成 LiOH 和 Li2CO3， 循环过程中这些副产物 与电解液反应， 不断在电极表面形成绝缘材料并消 耗电解液，从而阻碍了 Li + 在材料中的扩散 [15][16][17] 。 为了解决上述问题， 本研究采用微波辅助共沉 淀与高温固相结合的方法制备了高镍 LiNi0.8Mn0.2O2(NM-82)正极材料，相比于目前常见 的高温固相、溶胶凝胶和共沉淀法等，通过微波加 热，可以诱导或加速反应过程，同时提高反应选择 性和产率，得到的材料元素分布均匀，性能良好且 方法简单可控 [18][19] 。研究表明，添加 Co 元素可以 极大地提升正极氧化物的倍率和循环性能 [20][21] ，而 掺杂 Al 可以显著改善材料的整体结构和界面稳定 性 [22][23][24][25] [11,19]…”