Concerted Effect of Ion- and Electron-Conductive Additives on the Electrochemical and Thermal Performances of the LiNiCoMnO Cathode Material Synthesized by a Taylor-Flow Reactor for Lithium-Ion Batteries.

To address the issue that a single coating agent cannot simultaneously enhance Li-ion transport and electronic conductivity of Ni-rich cathode materials with surface modification, in the present study, we first successfully synthesized a LiNiCoMnO (NCM811) cathode material by a Taylor-flow reactor followed by surface coating with Li-BTJ and dispersion of vapor-grown carbon fibers treated with polydopamine (PDA-VGCF) filler in the composite slurry. The Li-BTJ hybrid oligomer coating can suppress side reactions and enhance ionic conductivity, and the PDA-VGCFs filler can increase electronic conductivity. As a result of the synergistic effect of the dual conducting agents, the cells based on the modified NCM811 electrodes deliver superior cycling stability and rate capability, as compared to the bare NCM811 electrode.

Two birds with one stone: One-pot concurrent Ta-doping and -coating on Ni-rich LiNiCoMnO cathode materials with fiber-type microstructure and Li-conducting layer formation.

A novel scalable Taylor-Couette reactor (TCR) synthesis method was employed to prepare Ta-modified LiNiCoMnO (T-NCM92) with different Ta contents. Through experiments and density functional theory (DFT) calculations, the phase and microstructure of Ta-modified NCM92 were analyzed, showing that Ta provides a bifunctional (doping and coating at one time) effect on LiNiCoMnO cathode material through a one-step synthesis process via a controlling suitable amount of Ta and Li-salt. Ta doping allows the tailoring of the microstructure, orientation, and morphology of the primary NCM92 particles, resulting in a needle-like shape with fine structures that considerably enhance Li ion diffusion and electrochemical charge/discharge stability.