Communication - Pressure Evolution in Constrained Rechargeable Lithium-metal Pouch Cells

Understanding the role of pressure on improving cycle life for high energy rechargeable lithium metal batteries (LMBs) is crucial for their adoption in practical applications. In this work, a fixed-gap test fixture is developed to monitor stack pressure of a multi-layer, 300 Wh kg^-1 LMB over 245 cycles. During early cycling, a linear fade in discharge capacity is mirrored by a steady increase in baseline pressure. In later cycles, cell failure is linked to a large increase in baseline pressure due to irreversible side reactions such as continued SEI formation and gas evolution, as corroborated by incremental capacity analysis.