Preserving Power: The Role of Rest Periods in Lithium-Metal Battery Degradation

Dew Briefs:

• Researchers at Stanford University have made a significant discovery in improving the battery’s cycle life
• Electric vehicles could potentially have their range doubled by utilizing lithium metal batteries
• The simple solution involves allowing the battery to rest for several hours in a discharged state

Diver Insights:

• Rest periods after battery discharge have been found to be beneficial in lithium-metal batteries.
• Lithium-metal batteries utilize metallic lithium as the anode.
• Calendar ageing, which involves resting the batteries without an applied current or voltage, is believed to cause degradation in these batteries.
• This degradation permanently reduces the battery’s charge capacity and lowers its performance.
• The loss of battery capacity is typically caused by irreversible reactions between lithium metal and the battery’s electrolyte.
• It can also be attributed to lithium metal becoming electrically isolated from the rest of the anode.
• Zhang et al. have published a paper in Nature discussing their findings on the reconnection of electrically isolated lithium metal to the anode after calendar ageing.
• The reconnection of lithium metal to the anode can help improve battery performance.
• Rest periods can potentially solve the problem of lithium grains becoming electrically isolated from the anode.
• Lithium-metal batteries are considered a promising option for the next generation of rechargeable batteries.

A Brighter Future for EVs:
Stanford’s Restorative Method Propels Lithium Metal Battery Efficiency

1. Lithium metal batteries have the potential to revolutionize the electric vehicle industry by offering a significantly longer range on a single charge compared to conventional lithium-ion batteries. However, these batteries suffer from a major drawback – they rapidly lose their energy storage capacity after a few charging and discharging cycles. This poses a challenge for electric car drivers who rely on their vehicles to operate efficiently for years.
2. To address this issue, researchers at Stanford University have made an exciting discovery. By simply draining the battery and allowing it to rest for several hours, they were able to restore its capacity and enhance its overall performance. This cost-effective solution could have a significant impact on the future of electric vehicles, as it requires no additional equipment, materials, or changes in production flow.
3. The findings of this study offer valuable insights for EV manufacturers, as they strive to adapt lithium metal technology to real-world driving conditions. With the ability to recover lost capacity and increase cycle life through a simple reprogramming of the battery management software, the practical implications of this research are promising. As the demand for electric vehicles continues to grow, advancements in battery technology will play a crucial role in meeting the needs of drivers and making electric transportation more accessible and convenient.

Role of Li-ion and Li-Metal Batteries:

• Conventional lithium-ion batteries have graphite anodes and lithium metal oxide cathodes, separated by an electrolyte.
• Lithium metal batteries replace the graphite anode with lithium metal, doubling energy storage capacity.
• Lithium metal anodes are advantageous for electric vehicles due to their lighter weight.
• Lithium metal batteries can hold at least a third more energy per pound than lithium-ion batteries.
• Cars with lithium metal batteries can have twice the range of lithium-ion vehicles of the same size.
• The goal in EVs is to extend range while keeping the battery lightweight.
• Doubling EV range could alleviate range anxiety for potential buyers.
• However, lithium metal batteries degrade rapidly with continuous charging and discharging, making them unsuitable for regular driving.
• During discharge, lithium metal becomes isolated and trapped in the solid electrolyte interphase (SEI).
• The SEI matrix prevents isolated lithium metal from participating in electrochemical reactions, rendering it inactive and referred to as “dead lithium.”