Thermal Stability Enhancement through Structure Modification on the Microsized Crystalline Grain Surface of Lithium-Rich Layered Oxides

Abstract

Lithium-rich layered oxides have been considered as the most promising candidate for offering a high specific capacity and energy density for lithium-ion batteries. However, their practical applications are still suffered by the cycle instability and also closely related thermal stability. Here, microsized crystalline grains with good dispersion of lithium-rich layered oxides are prepared by a molten-salt method, while a spinel structure is also introduced on a grain surface by following chemical oxidation and annealing process, and their thermal performance with different cutoff voltages during the charge process is systematically studied using differential scanning calorimetry method. Results have shown that thermal stability of microsized crystalline grains is better than that of spherical secondary agglomerates, the spinel structure introduction on the grain surface of microsized crystalline grains can contribute obviously to their thermal stability, in which the onset temperature of the exothermic peak has been increased by 103 °C, and the thermal release value can be reduced as much as about 40% when the battery was charged to 4.8 V. Furthermore, the electrochemical performance, especially cycle stability under a high temperature, has also been enhanced for spinel-modified microsized crystalline grains. This work not only develops the microsized crystalline grains with good dispersion of lithium-rich layered oxides, confirming the advantages of these materials compared to spherical secondary agglomerates, but also reveals the method to improve their thermal stability by grain surface structure modification, opening the way to optimize the comprehensive performance of electrode materials for batteries.

Composite Nanostructure Construction on the Grain Surface of Li‐Rich Layered Oxides

“…[17,18] A further integration of compatible spinel structures at the LLO's grain surface, either by post introduction or in situ growth, may provide new functional units to improve the rate performance of LLOs. [19,20] The effects of spinel structure are highly dependent on their intrinsic properties and integrated configurations with LLOs. However, spinel structure often appears as irregular particles or Li-rich layered oxides (LLOs) are fascinating high-energy cathodes for lithium-ion batteries (LIBs), but still suffer from critical drawbacks that retard their practical applications.…”

One‐step Preparation of Conducting Polymer/Metal Oxide Doped RGO Trinary Composite for Supercapacitor Applications

“…As per the FTIR data of GO, we can determine that graphite has successfully oxidized. As per FTIR spectra of RPM, the major peaks observed at 3205 cm −1 for ‐OH bond stretching, 2905 cm −1 symmetric and asymmetric stretching vibrations of CH 2 , 1580 cm −1 for benzenoid, 1494 cm −1 quinoid, 1295 cm −1 for polymeric C−N, 1126 cm −1 C−H in‐plane bending, 1012 cm −1 for C−O stretching . These relative peaks indicate polymerization has occurred of PANI.…”

“…The heteroatoms such as N‐functionalized polar surface with conducting polymer and the metal oxide reflected to be substantial in charge‐storing ability as well as permit easy access of the electrolyte ions, also provides pseudocapacitance to graphene materials . The electrochemical performances of our RPM material done by CV, GCD and EIS using three‐electrode set‐up (Figure ).…”

“…Kai et al. performed electrodeposition synthesis of PANI/MnO 2 /Graphene composites, which achieved 1019 F/g specific capacitance at 0.5 A/g . Fu et al.…”

Insights into the estimation of capacitance for carbon-based supercapacitors

“…Namely, carbon materials, including activated carbons, graphene, carbide-derived carbons, and carbon nanotubes, have been employed due to their high conductivity, large specic surface area, low density, and good chemical stability. [8][9][10][11] In particular, the surface area is of great importance in the charge storage of the electrical double layer (EDL). A large surface area provides more available active sites for ions to interact, and consequently, the capacitance can be improved.…”