Search

NASICON‐type Li1.3Al0.3Ti1.7(PO4)3 (LATP) is one of the most promising solid‐state electrolytes (SSEs) to achieve high‐energy‐density solid‐state batteries (SSBs) due to its high ionic conductivity, high‐voltage stability, and low cost. However, its practical application is constrained by inadequate interfacial compatibility with cathode materials and significant incompatibility with lithium metal. In this work, a cost‐effective interface welding approach is reported, utilizing an innovative thermal pulse sintering (TPS) to fabricate LATP‐based solid‐state batteries. Initially, the rapid thermal pulses enhance the ionic conductivity of LATP SSE by inducing selective growth of LATP nanowires, effectively occupying interparticle voids. Additionally, this process results in the formation of a dense layer (GCM) comprising graphene oxide, carbon nanotubes, and MXene with a controlled Li+ transport pathway, facilitating lithium stripping and plating processes. Moreover, these thermal pulses facilitate the interfacial fusion between LATP and cathode materials, while avoiding undesired phase diffusion. As a result, SSBs with a LiCoO2 cathode deliver favorable cycle stability at 4.6 V, marking significant progress. This facile interface welding strategy represents a substantial step toward high‐energy‐density SSB development. [ABSTRACT FROM AUTHOR]

Due to the existence of a small polaron, the intrinsic electronic conductivity of olivine-structured LiFePO4 is quite low, limiting its performance as a cathode material for lithium-ion batteries (LIBs). Previous studies have mainly focused on improving intrinsic conductivity through Fe-site doping while P-site or O-site doping has rarely been reported. Herein, we studied the formation and dynamics of the small electron polaron in FeP1−αXαO4 and FePO4−βZβ by employing the density functional theory with the on-site Hubbard correction terms (DFT+U) and Kinetic Monte Carlo (KMC) simulation, where X and Z indicate the doping elements (X = S, Se, As, Si, V; Z = S, F, Cl), and α and β indicate the light doping at the P position (α = 0.0625) and O position (β = 0.015625), respectively. We confirmed the small electron polaron formation in pristine FePO4 and its doped systems, and the polaron hopping rates for all systems were calculated according to the Marcus–Emin–Holstein–Austin–Mott (MEHAM) theory. We found that the hopping process is adiabatic for most cases with the defects breaking the original symmetry. Based on the KMC simulation results, we found that the doping of S at the P site changes the polaron's motion mode, which is expected to increase the mobility and intrinsic electronic conductivity. This study attempts to provide theoretical guidance to improve the electronic conductivity of LiFePO4-like cathode materials with better rate performance. [ABSTRACT FROM AUTHOR]

Due to the existence of a small polaron, the intrinsic electronic conductivity of olivine-structured LiFePO 4 is quite low, limiting its performance as a cathode material for lithium-ion batteries (LIBs). Previous studies have mainly focused on improving intrinsic conductivity through Fe-site doping while P-site or O-site doping has rarely been reported. Herein, we studied the formation and dynamics of the small electron polaron in FeP 1- α X α O 4 and FePO 4- β Z β by employing the density functional theory with the on-site Hubbard correction terms (DFT+ U ) and Kinetic Monte Carlo (KMC) simulation, where X and Z indicate the doping elements (X = S, Se, As, Si, V; Z = S, F, Cl), and α and β indicate the light doping at the P position ( α = 0.0625) and O position ( β = 0.015625), respectively. We confirmed the small electron polaron formation in pristine FePO 4 and its doped systems, and the polaron hopping rates for all systems were calculated according to the Marcus-Emin-Holstein-Austin-Mott (MEHAM) theory. We found that the hopping process is adiabatic for most cases with the defects breaking the original symmetry. Based on the KMC simulation results, we found that the doping of S at the P site changes the polaron's motion mode, which is expected to increase the mobility and intrinsic electronic conductivity. This study attempts to provide theoretical guidance to improve the electronic conductivity of LiFePO 4 -like cathode materials with better rate performance.