(Invited) Towards Deterministic 3D Li-Ion Electrode Architectures Via Electrodeposition of Molybdenum Oxide Onto CNT Foams

Abstract

Three-dimensional (3D) deterministic design of electrodes could enable simultaneous high energy and power density for electrochemical energy storage devices. The goal of such electrode architectures is to provide adequate charge (electron and ion) transport pathways for high power while maintaining high active material loading (> 10 mg cm-2) for high areal and volumetric capacity. However, it remains a challenge to fabricate such electrodes with processes that are both scalable and reproducible. Towards this end, I will discuss how the fabrication of such an electrode is made possible by combining highly tunable, free-standing, and aligned CNT foams with aqueous electrodeposition of a model intercalation-type transition metal oxide, MoO3. Morphological characterization including X-ray micro computed tomography indicate that the obtained composite is highly homogenous. Electrodes with active mass loading up to 18 mg cm-2 can reach near-theoretical Li-ion intercalation capacities within 1.7 hours. The highest mass loading electrodes also led to areal and volumetric capacities of 4.5 mAh cm-2 and 290 mAh cm-3 with 55% capacity retention for charge/discharge times of 10 minutes. I will also describe the use of mesoscale modeling to understand and ultimately, predict the performance of this electrode architecture. Overall, our work demonstrates a scalable, deterministic 3D electrode design strategy using electrodeposition and free-standing, aligned CNT foams that lead to high areal and volumetric capacities and good rate performance due to well-distributed charge transport pathways.