Design and laser processing of laminated 3D network for high-performance electrodes of metal-ion batteries

High-performance metal-ion batteries are crucial to electronic devices, electric vehicles and large-scale energy storage applications. High mass-loading of electrode materials is essential to achieve high volumetric capacity and thus high energy density of batteries. However, the loading density is severely constrained by the instable electrode structure, sluggish ion diffusion, low e^- transportation and inferior electrochemical performance of high-loading electrodes. Here, an integrated strategy of designing and processing laminated 3D network by femtosecond laser technology is proposed and carried out to construct high-loading Li₄Ti₅O₁₂ (LTO) anodes with high capacity, high rate and long lifetime performances for lithium-ion batteries. The laminated 3D electrode is constituted of a 3D porous current collector with an array of microporous networks and a 3D LTO layer with an interdigitated array of microgroove networks. With such a laminated 3D structure, not only are the current collectors and the electrode materials tightly interlocked, but also a series of interconnected fast charge (Li⁺/e^-) transfer channels are formed. Therefore, the structure stability, electrochemical kinetics, specific capacity, rate capability and cycling stability of high-loading electrodes are significantly improved as demonstrated by both computation study and experimental verification. The optimized LTO electrode could deliver a high volumetric capacity of 136 mA h cm^-3 at 60 C and a fast Li⁺ diffusivity of 4.28 × 10^-12 cm²/s, which is 2.82 and 107.54 times higher than that of the untreated electrode, respectively. This work provides a novel route of designing and preparing high-performance, high-loading electrodes for metal-ion batteries.