Periodically aligned channels in Li[Ni0.5Co0.2Mn0.3]O2 cathodes designed by laser ablation for high power Li ion batteries

Abstract

Lithium-ion batteries are widely used in electric vehicles (EVs) owing to their high energy density and cycling stability. However, achieving high driving mileage per charging time under high electrode mass loading remains a significant challenge for high performance EVs. Herein, a new strategy to improve the rate capability of thick electrodes is proposed based on the laser ablation, which generates periodically aligned channels in the electrodes. To investigate the effect of porosity and interfacial area on the power performance, Li[Ni0.5Co0.2Mn0.3]O-2 cathode-based laser-processed electrodes (LPEs) are fabricated by adjusting the spacing and depth of channels. Comparing the relative capacity of C-16C/C-0.25C, LPEs shows improved value of 19.83%, whereas the conventional electrodes (CEs) of 0.08%. Furthermore, the rate capability of LPEs is superior to that of CEs under the same mass loading, arising from the formation of the channels rather than the mass loss evolved during the laser ablation. The exceptional rate capability of LPEs is attributed to the alleviated activation/concentration polarization, enhanced Li-ion diffusion kinetics, and reduced tortuosity. The laser ablation is an effective strategy, as it can be compatible with any cathode and anode materials.