Improved Rate Capability in Composite Solid-State Battery Electrodes Using 3-D Architectures

Abstract

The limited rate capability observed at faster charging rates is a critical challenge for composite electrodes in solid-state batteries (SSBs). This becomes further amplified with increasing electrode thickness and higher ratios of active material to solid electrode, which result in tradeoffs between energy and power density. To overcome these trade-offs, it is necessary to understand the factors responsible for poor rate capability by exploring new approaches to boost power density without compromising energy density. Herein, we fabricated 3-D patterned composite graphite (Gr/Li 6 PS 5 Cl) electrodes with low-tortuosity electrolyte channels using a templating approach. Graphite was chosen as a model system to study inhomogeneous lithiation in composite SSB electrode architectures because of the visible color changes that occur as a function of local state-of-charge. At faster cycling rates (1C), the 3-D patterned electrodes enabled considerably higher accessible capacity (38% increase) compared to the unpatterned control electrodes. These enhancements were visualized using operando video microscopy, where 3-D electrode architectures showed improved homogeneity in the local state-of-charge throughout the electrode thickness. The insights presented here will enable new strategies based on 3-D electrode architectures to overcome power/energy trade-offs in SSBs.

Interfacial dynamics of carbon interlayers in anode-free solid-state batteries

“…As described in our previous report, a planar cross-section was prepared by cutting and polishing one edge of the pellet. 50,51 As we have previously shown, the SOC gradients observed along this polished cross-section are consistent with those deeper within the bulk of the pellet. 50,51 The cell stack was assembled into a custom visualization fixture, which was maintained at a constant stack pressure of 5 MPa and a temperature of 60 °C for cycling.…”

“…50,51 As we have previously shown, the SOC gradients observed along this polished cross-section are consistent with those deeper within the bulk of the pellet. 50,51 The cell stack was assembled into a custom visualization fixture, which was maintained at a constant stack pressure of 5 MPa and a temperature of 60 °C for cycling. A Keyence 4k digital microscope and a BioLogic SP-200 potentiostat were used to perform the operando optical microscopy characterization.…”

“…35 This is consistent with previous operando video microscopy observations of graphite anodes in SSBs, where Li transport is limited through the electrode thickness. 50,51 After the lithiation step, the Li concentration gradient is allowed to relax during OCV, where after 5 hours, the gold particles closest to the SE interface start to transition to the red phase, while the phase boundary between red and blue has propagated towards the CC (Fig. 6d).…”

Computational approach inspired advancements of solid-state electrolytes for lithium secondary batteries: from first-principles to machine learning

“…Nonetheless, at high charge/discharge rates, the behavior of solid-state composite electrodes, particularly the spatial inhomogeneity in the local state-of-charge, requires investigation to assess the influence of electrode microstructures on rate capability. 270,271 Simulations have revealed Li concentration gradients within the active material, which arise from the depth of the electrode. The lithiation process occurs at a faster rate in certain regions of the electrode due to ionic conduction within the SE phase and the gradient in the electrostatic potential of the SE (Fig.…”

Understanding and unveiling the electro‐chemo‐mechanical behavior in solid‐state batteries

“…2 SSBs function by a similar mechanism to commercial liquid-based (rechargeable) batteries, which are charged and discharged by transporting lithium ions between the anode and cathode. However, as the liquid electrolyte is replaced by SSE, the solid-solid contact between the diverse components in the SSB presents more complex interfacial issues, [3][4][5][6][7][8][9][10] and therefore the development of SSBs is greatly hindered. In order to unveil the underlying science and engineering challenges, it is critical to study and track how lithium ions are transported and distributed in SSBs under working conditions.…”