Highly Aligned Graphene Oxide for Lithium Storage in Lithium‐Ion Battery Through A Novel Microfluidic Process: The Pulse Freezing

Abstract The modification of carbon‐based lithium‐ion batteries electrodes is required for the growing need of more reliable electric vehicles. Herein, a new method is introduced to fabricate vertically aligned graphene oxide (GO) films as free‐standing carbon lithium hosts for lithium‐ion batteries with enhanced performance. Vertical alignments are induced of GO in a microfluidic channel by controlling flow rates and patterns of GO suspensions. The vertical alignments are preserved and spontaneously form porous microstructures by Pulse Freezing the GO solutions inside the channel. This combined process results in the increase of levels of microstructure porosity and vertical alignment of GO films. The alignment and porous microstructures increase both electron and ion transfer capabilities across the prepared film. The half‐cell performance of aligned GO films shows a specific capacity of 440 mAh g⁻¹ at a current density of 0.5 A g⁻¹ after 150 cycles. This is a 190% specific capacity increase compared to the performance of a half‐cell prepared with GO without the high level of vertical alignment and microporosity. The significant increase in the value and stability of specific capacity and higher rates of charge transfer favor the promising application of carbon‐based lithium‐ion batteries for electric transportation industries.