Improved Lithium-Ion Transport Within the LiNi0.8Co0.15Al0.05O2 Secondary Cathode Particles Through a Template-Assisted Synthesis Route

Herein, we report a sacrificial carbon fiber (CF) template-assisted synthesis of LiNi0.8Co0.15Al0.05O2 (C-NCA) by the Pechini method. An anisotropic primary particle morphology with an interconnected microstructure is obtained, originating from local overheating and oxygen-deficient zones induced by combustion of the CFs during high-temperature lithiation. Moreover, the particles assembled around the CFs demonstrated denser packing compared to the reference bare NCA (B-NCA) synthetized in the absence of the CF template. The anisotropic surfaces facilitate ion transport and stabilize the structure for high voltage and temperature operation. C-NCAllLi metal cells exhibit a reversible capacity of 106 mA h g(-1) at 10 C and are able to retain 96% of their initial capacity as the C-rate is reverted to 0.1 C. The state of health of C-NCAllgraphite full cells remains at 70% after 200 cycles at 0.33 C within 2.8-4.3 V. The results outperform the B-NCA cell, exhibiting a significant loss over 66 cycles while delivering only 50% of its initial capacity. The synthesis method allows for a straightforward route for tailoring the particle size, shape, and crystallinity, enabling the development of stable nickel-rich cathode materials, even at an upper cutoff voltage of 4.5 V or an operating temperature of 60 degrees C.

Automated summary

In this study, a sacrificial carbon fiber template was used to synthesize LiNi0.8Co0.15Al0.05O2 (C-NCA) cathode material, which exhibited high reversible capacity and stability suitable for high-rate and high-temperature battery operation. The anisotropic primary particle morphology with interconnected microstructure played a key role in improving ion transport and structural stability, outperforming the reference bare NCA material.