Microwave‐Assisted Synthesis of Co₃O₄ Sheets for Reversible Li Storage: Regulation of Structure and Performance

Abstract

To elucidate the relationship between the structure and Listorage performances, a controllable and porous nanosheetshaped Co 3 O 4 material (Co 3 O 4 -AS) was constructed from nanob-Co(OH) 2 precursor, which was obtained from a common Co (NO 3 ) 2 solution without any templates under microwave radiation conditions. A probable assembly mechanism is proposed on the basis of various analyses and comparisons. After its structure was characterized by using SEM, XRD, TEM, and N 2 absorption/desorption isotherms, Co 3 O 4 -AS was effec-tively applied an a highly reversible Li-storage anode in a lithium-ion battery, with a reversible capacity of 920 mAh g À1 after 100 cycles and even a capacity of 445 mAh g À1 at 5C. The improved properties could be attributed to the remarkable synergistic effects between porous structures and sheet-shaped morphologies, resulting in short and facile diffusion, good electronicÀionic conductivity, and structural stability during cycling.[a] Dr.

Crystal‐Plane‐Dependent Activity of Spinel Co3O4 Towards Water Splitting and the Oxygen Reduction Reaction

“…Developing eco‐benignity and high performance electrocatalysts for clean energy conversation and storage is motivated by increasing demand for global energy security and sustainable technologies depend on abundant and inexpensive resources . Recently, the high efficiency and low price of spinel oxides, such as Co 3 O 4 , attracted much attention as electrocatalysts for OER, ORR and HER which played the vital roles in clean energy for metal‐air batteries, fuel cells and water electrolyzers .…”

Crosslinked MnO2 Nanowires Anchored in Sulfur Self‐Doped Porous Carbon Skeleton with Superior Lithium Storage Performance

“…LIBs have attracted great attention because of its high energy density and long cycling life. To supersede the commercial graphite anode which has a limited theoretical capacity of 372 mAh/g, many metal oxides such as Co 3 O 4 , MnO 2 and SnO 2 , owing to their significantly higher theoretical specific capacities, have attracted wide interest as potential anode materials. As a typical metal oxide, MnO 2 possesses many merits, such as natural abundance, environmental friendliness, cost effectiveness, low toxicity and high theoretical capacity up to 1232 mAh/g ,.…”

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]…”