Abstract: Described herein are methods and systems for restoring LiMLE cells by cycling such cells using restoring conditions comprising specially selected restoring discharge current (e.g., at least 1 D) and a restoring charge current (e.g., less than 0.5 C). This restoration cycling can be triggered when a LiMLE cell reaches a restoring threshold, determined based on one or more of the following operating and resting conditions: a discharge capacity, an overpotential, an impedance, a direct-current (DC) resistance, the rest period duration, an open circuit voltage, operating discharge and/or charge currents, and an operating cycle count. The restoring threshold is selected to reflect the negative electrode state in a LiMLE cell. The restoring conditions are selected to change this negative electrode state to improve the performance of the LiMLE cell. For example, the restoring discharge can reduce the cell's state of charge (SOC) by at least 10%.

Abstract: Described herein are methods and systems for controlling the charge and discharge characteristics of lithium-metal liquid-electrolyte (LiMLE) electrochemical cells that ensure extended cycle life even at high charge rates. In some examples, a method comprises charging a LiMLE electrochemical cell using a set of charge characteristics and discharging the cell using a set of discharge characteristics. These characteristics are specifically tailored to the cell design. For example, the cell temperature can be higher during the charge than during the discharge, especially for viscous electrolytes. For example, the cell can be heated before charging, e.g., using a separate heater and/or charge-discharge pulses (before or while charging the cell). In the same or other examples, the set of charge characteristics comprises charge pulses such that each pair of charge pulses is separated by a discharge pulse. The current during each discharge pulse can be greater during each charge pulse.