Electrochemical and Structural Investigations on ZnO Treated 0.5 Li₂MnO₃-0.5LiMn_0.5Ni_0.5O₂Layered Composite Cathode Material for Lithium Ion Battery

Abstract

0.5Li 2 MnO 3 -0.5LiMn 0.5 Ni 0.5 O 2 composite cathode material with and without ZnO treatment has been synthesized using carbonate based co-precipitation method for rechargeable lithium ion battery. The X-ray diffraction study confirms that the material has layered LiNi 0.5 Mn 0.5 O 2 structure along with the formation of the superlattice ordering of Li 2 MnO 3 ; without any major change in the crystal structure with ZnO treatment. Raman spectroscopy has revealed two different types of ionic arrangements corresponding to space groups of C2/m and R3m for Li 2 MnO 3 and LiNi 0.5 Mn 0.5 O 2 respectively. Morphological studies revealed primary particles are of ∼1 micron size and have sharp, elongated edges. The particles are present as spherical agglomerates (∼10 micron). Elemental mapping and X-ray photoelectron spectroscopy confirmed the presence of Zn in the ZnO treated samples. Charge/discharge capacity of the composite cathode materials (with and without ZnO coating) increases with number of cycles due to more and more activation of the Li 2 MnO 3 . However, ZnO treated 0.5Li 2 MnO 3 -0.5LiMn 0.5 Ni 0.5 O 2 composite material showed higher charge/discharge capacites attaining saturation in less number of cycles. Lower resistance to charge transfer in the case of ZnO treated sample is responsible for its better performance.

Improved Electrochemical Performance and Thermal Stability of Li-excess Li1.18Co0.15Ni0.15Mn0.52O2 Cathode Material by Li3PO4 Surface Coating

“…Surface coating has been an effective method to overcome these problems. The most commonly used coating materials are metal oxides such as TiO 2 , ZnO, Al 2 O 3 , ZrO 2 , MgO [12][13][14][15][16][17], or fluorides such as CaF 2 and AlF 3 [18,19]. Besides these, carbonaceous materials [20], conductive polymers such as polyaniline (PANI) and polypyrrole (Ppy) have been used to increase the electronic conductivity of Li-excess layered oxides [21,22].…”

Fluoroethylene Carbonate as Electrolyte Additive for Improving the electrochemical performances of High-Capacity Li1.16[Mn0.75Ni0.25]0.84O2 Material

“…In order to solve the problem, strategies have been proposed to stabilize the cathode crystal structure and the cathode/electrolyte interface. Coating the material with AlF 3 , FePO 4 or ZnO is an approach to enhance structural stability of the cathode material and prevent direct contact between the active material and the electrolyte [11][12][13][14]. In addition, a native surface film mainly composed of Li 2 CO 3 appears on the transition metal oxide cathode during electrode manufacturing/ processing.…”

Design and Preparation of a Lithium‐rich Layered Oxide Cathode with a Mg‐Concentration‐Gradient Shell for Improved Rate Capability

“…[33,38,39] The clear splitting of the (006)/(102) and (108)/(110) peaks for the cathodem aterials CSLM and CL indicatesawell-organized layered structure. [23,40] In addition, no impurity peaks relatedt o the Mg-related compounds can be observed by XRD. The lattice parameters of the cathode materials CSLM and CL were calculated from the XRD pattern by Rietveld refinements, by using only the R3m space group.…”

“…One approach to enhancet he electrochemicalp roperties of this materiali st oc oat the oxide particles with an anoscale metal compound, which can prevent active substances from being in directc ontact with the electrolyte, resulting in less side reactions and HF attack. [20][21][22][23] However,t he nanoscale coating layer is so thin and heterogeneous that it can wear off during long-term charge/discharge cycle processes,i fi ti ss ubjected to continuous HF attack, thus resulting in capacity fading during extensive cycling. [24,25] Recently,t here has been al ot of interesti nf abricating materials with distinctive "core-shell" configurations, [25][26][27][28] owing to their superior structural characteristics ande lectrochemical properties.…”