Limits...
Facile preparation of core@shell and concentration-gradient spinel particles for Li-ion battery cathode materials

View Article: PubMed Central - PubMed

ABSTRACT

Core@shell and concentration-gradient particles have attracted much attention as improved cathodes for Li-ion batteries (LIBs). However, most of their preparation routes have employed a precisely-controlled co-precipitation method. Here, we report a facile preparation route of core@shell and concentration-gradient spinel particles by dry powder processing. The core@shell particles composed of the MnO2 core and the Li(Ni,Mn)2O4 spinel shell are prepared by mechanical treatment using an attrition-type mill, whereas the concentration-gradient spinel particles with an average composition of LiNi0.32Mn1.68O4 are produced by calcination of their core@shell particles as a precursor. The concentration-gradient LiNi0.32Mn1.68O4 spinel cathode exhibits the high discharge capacity of 135.3 mA h g−1, the wide-range plateau at a high voltage of 4.7 V and the cyclability with a capacity retention of 99.4% after 20 cycles. Thus, the facile preparation route of the core@shell and concentration-gradient particles may provide a new opportunity for the discovery and investigation of functional materials as well as for the cathode materials for LIBs.

No MeSH data available.


Related in: MedlinePlus

SEM images and EDX elemental maps for the (a), (b) starting powder and (c)–(f) mechanically treated product. Elemental maps of oxygen, nickel and manganese are shown in green, purple and yellow, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC5036501&req=5

Figure 2: SEM images and EDX elemental maps for the (a), (b) starting powder and (c)–(f) mechanically treated product. Elemental maps of oxygen, nickel and manganese are shown in green, purple and yellow, respectively.

Mentions: The SEM-EDS elemental maps of the stating powder and the mechanically treated product are shown in figure 2. The mechanically treated product indicates the cross-sectional view of the particles. The starting powder consisted of the micrometer-sized MnO2 particles with an irregular shape and the fine particles of Li2CO3 and NiO (figures 2(a), (b)). The product with a spherical shape was obtained by mechanical treatment of the starting powder using an attrition-type mill (figure 2(c)). A cross-sectional observation of the product revealed the deposition of nanometer-sized particles onto the surface (figure 2(c), inset figure). The EDS maps of oxygen, nickel and manganese clearly exhibited that the mechanically treated product had a core@shell structure and that the shell was constructed by the deposited particles (figures 2(d)–(f)). Nickel was detected in the surface layer of the product particle, while oxygen and manganese were homogeneously distributed. Thus, the core is attributed to a MnO2 phase. The XRD pattern of the product, which is shown later, indicated a Ni-doped LiMn2O4 phase, i.e. a Li(Ni,Mn)2O4 spinel. Consequently, the MnO2@Li(Ni,Mn)2O4 core@shell particles could be prepared by the simple mechanical process without external heating.


Facile preparation of core@shell and concentration-gradient spinel particles for Li-ion battery cathode materials
SEM images and EDX elemental maps for the (a), (b) starting powder and (c)–(f) mechanically treated product. Elemental maps of oxygen, nickel and manganese are shown in green, purple and yellow, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036501&req=5

Figure 2: SEM images and EDX elemental maps for the (a), (b) starting powder and (c)–(f) mechanically treated product. Elemental maps of oxygen, nickel and manganese are shown in green, purple and yellow, respectively.
Mentions: The SEM-EDS elemental maps of the stating powder and the mechanically treated product are shown in figure 2. The mechanically treated product indicates the cross-sectional view of the particles. The starting powder consisted of the micrometer-sized MnO2 particles with an irregular shape and the fine particles of Li2CO3 and NiO (figures 2(a), (b)). The product with a spherical shape was obtained by mechanical treatment of the starting powder using an attrition-type mill (figure 2(c)). A cross-sectional observation of the product revealed the deposition of nanometer-sized particles onto the surface (figure 2(c), inset figure). The EDS maps of oxygen, nickel and manganese clearly exhibited that the mechanically treated product had a core@shell structure and that the shell was constructed by the deposited particles (figures 2(d)–(f)). Nickel was detected in the surface layer of the product particle, while oxygen and manganese were homogeneously distributed. Thus, the core is attributed to a MnO2 phase. The XRD pattern of the product, which is shown later, indicated a Ni-doped LiMn2O4 phase, i.e. a Li(Ni,Mn)2O4 spinel. Consequently, the MnO2@Li(Ni,Mn)2O4 core@shell particles could be prepared by the simple mechanical process without external heating.

View Article: PubMed Central - PubMed

ABSTRACT

Core@shell and concentration-gradient particles have attracted much attention as improved cathodes for Li-ion batteries (LIBs). However, most of their preparation routes have employed a precisely-controlled co-precipitation method. Here, we report a facile preparation route of core@shell and concentration-gradient spinel particles by dry powder processing. The core@shell particles composed of the MnO2 core and the Li(Ni,Mn)2O4 spinel shell are prepared by mechanical treatment using an attrition-type mill, whereas the concentration-gradient spinel particles with an average composition of LiNi0.32Mn1.68O4 are produced by calcination of their core@shell particles as a precursor. The concentration-gradient LiNi0.32Mn1.68O4 spinel cathode exhibits the high discharge capacity of 135.3 mA h g−1, the wide-range plateau at a high voltage of 4.7 V and the cyclability with a capacity retention of 99.4% after 20 cycles. Thus, the facile preparation route of the core@shell and concentration-gradient particles may provide a new opportunity for the discovery and investigation of functional materials as well as for the cathode materials for LIBs.

No MeSH data available.


Related in: MedlinePlus