Solid-state attachments of Ag nanoparticles onto the surfaces of LiFePO4 cathode materials for Li storage with enhanced capabilities

Silver Nanocoating of LiNi0.8Co0.1Mn0.1O2 Cathode Material for Lithium-Ion Batteries

Surface coating has become an effective approach to improve the electrochemical performance of Ni-rich cathode materials. In this study, we investigated the nature of an Ag coating layer and its effect on electrochemical properties of the LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathode material, which was synthesized using 3 mol.% of silver nanoparticles by a facile, cost-effective, scalable and convenient method. We conducted structural analyses using X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy, which revealed that the Ag nanoparticle coating did not affect the layered structure of NCM811. The Ag-coated sample had less cation mixing compared to the pristine NMC811, which could be attributed to the surface protection of Ag coating from air contamination. The Ag-coated NCM811 exhibited better kinetics than the pristine one, which is attributed to the higher electronic conductivity and better layered structure provided by the Ag nanoparticle coating. The Ag-coated NCM811 delivered a discharge capacity of 185 mAh·g^-1 at the first cycle and 120 mAh·g^-1 at the 100th cycle, respectively, which is better than the pristine NMC811.

Ag-Modified LiMn2O4 Cathode for Lithium-Ion Batteries: Coating Functionalization

In this work, the properties of silver-modified LiMn2O4 cathode materials are revisited. We study the influence of calcination atmosphere on the properties of the Ag-coated LiMn2O4 (Ag/LMO) and highlight the silver oxidation. The effect of the heat treatment in vacuum is compared with that in air by the characterization of the structure, specific surface area, Li transport properties and electrochemical performance of Ag/LMO composites. Surface analyses (XPS and Raman spectroscopy) show that the nature of the coating (~3 wt.%) differs with the calcination atmosphere: Ag/LMO(v) calcined in vacuum displays Ag nanospheres and minor AgO content on its surface (specific surface area of 4.1 m2 g−1), while Ag/LMO(a) treated in air is mainly covered by the AgO insulating phase (specific surface area of 0.6 m2 g−1). Electrochemical experiments emphasize that ~3 wt.% Ag coating is effective to minimize the drawbacks of the spinel LiMn2O4 (Mn dissolution, cycling instability, etc.). The Ag/LMO(v) electrode shows high capacity retention, good cyclability at C/2 rate and capacity fade of 0.06% per cycle (in 60 cycles).

Cuprous Self-Doping Regulated Mesoporous CuS Nanotube Cathode Materials for Rechargeable Magnesium Batteries

Copper sulfides are broadly explored as the possible cathode materials for rechargeable magnesium batteries on account of their high theoretical capacity of 560 mAh g^-1. However, the CuS cathodes usually suffer from serious capacity decay caused by structure collapse during the repeated magnesiation/demagnesiation process. Herein, we present a cuprous self-doping strategy to synthesize mesoporous CuS nanotubes with robust structural stability for rechargeable magnesium batteries and regulate their electrochemical magnesium storage behavior. Electrochemical results show that the mesoporous CuS nanotubes can exhibit high specific capacity, remarkable cycling performance, and good rate capability. The observed discharge capacity of the mesoporous CuS nanotubes could reach about 281.2 mAh g^-1 at 20 mA g^-1 and 168.9 mAh g^-1 at 500 mA g^-1. Furthermore, a remarkable ultralong-term cyclic stability with a reversible capacity of 72.5 mAh g^-1 at 1 A g^-1 is obtained after 550 cycles. These results demonstrate that the mesoporous nanotube structure and the simple cuprous self-doping effect could promote the practical application of copper sulfide cathode materials for rechargeable magnesium batteries.