A 5V-class Cobalt-free Battery Cathode with High Loading Enabled by Dry Coating

Abstract

Transitioning toward more sustainable materials and manufacturing methods will be critical to continue supporting the rapidly expanding market for lithium-ion batteries. Meanwhile, energy storage applications are demanding higher power and energy densities than ever before, with aggressive performance targets like fast charging and greatly extended operating ranges and durations. Due to its high operating voltage and cobalt-free chemistry, the spinel-type LiNi0.5Mn1.5O4 (LNMO) cathode material has attracted great interest as one of the few next-generation candidates capable of addressing this combination of challenges. However, severe capacity degradation and poor interphase stability have thus far impeded the practical application of LNMO. In this study, by leveraging a dry electrode coating process, we demonstrate LNMO electrodes with stable full cell operation (up to 68% after 1000 cycles) and ultra-high loading (up to 9.5 mAh/cm2 in half cells). This excellent cycling stability is ascribed to a stable cathode-electrolyte interphase, a highly distributed and interconnected electronic percolation network, and robust mechanical properties. High-quality images collected using plasma focused ion beam scanning electron microscopy (PFIB-SEM) provide additional insight into this behavior, with a complementary 2-D model illustrating how the electronic percolation network in the dry-coated electrodes more efficiently supports homogeneous electrochemical reaction pathways. These results strongly motivate that LNMO as a high voltage cobalt-free cathode chemistry combined with an energy-efficient dry electrode coating process opens the possibility for sustainable electrode manufacturing of cost-effective and high-energy-density cathode materials.

Demarcating the Impact of Electrolytes on High‐Nickel Cathodes and Lithium‐Metal Anode

“…This can correlate to the uniformity of the CEI layer where LP57 may form a large difference in CEI thickness and the CEI may not entirely cover the LNO surface at the area of measurement. [55] The lower amounts of C and O are compensated with a higher amount of F species in LHCE, including LiF at 685.5 eV and C-F from the PVDF binder at 688.4 eV. Note that there is a small peak of Li x PF y for LP57 due to the decomposition of LiPF 6 salts.…”

High‐Loading Lithium‐Sulfur Batteries with Solvent‐Free Dry‐Electrode Processing

“…As it offers the distinct advantage of eliminating the use of organic or aqueous solvents that can sensitively react with solid-state electrolytes, the dry-processing method is especially useful for the sulfur-based cathodes in allsolid-state batteries. [42][43][44] However, another advantage of dryprocessing, the ability to produce extremely thick electrodes without cracking, [45][46][47] suggests that this fabrication method could also be significant for Li-S systems with liquid electrolytes. Indeed, sulfur has a soft nature, making it amenable to dry processing and easy to roll.…”