Enhancing Lithium-Ion Battery Performance: The Role of Electrolyte Additives

The performance of lithium-ion batteries is influenced significantly by the choice of materials and additives used in their construction. Recent research indicates that the alloy composition of anodes can enhance stability and cycle life. For instance, studies have shown that lithium anodes can endure over 300 cycles, maintaining decent efficiency despite observable capacity loss. A promising approach involves pretreating electrolytes with lithium metal, which has been shown to facilitate reversible plating and stripping, particularly on aluminum substrates.

Adding hydrochloric acid (HCl) to lithium chloride-buffered melts has been identified as a method to improve the reversibility of lithium cycling. This effect is particularly notable for lithium compared to sodium, with high current efficiencies exceeding 90% observed in short voltammetric tests. However, prolonged exposure to the electrolyte leads to the formation of a brown film on the plated lithium, which diminishes charge efficiency dramatically over time, illustrating the ongoing challenges in stabilizing lithium deposits.

Innovative strategies to enhance lithium cycling stability include the introduction of various additives such as TEOA and thionyl chloride. These substances not only improve plating morphology but also lower nucleation polarization, benefiting overall efficiency. While adding these compounds has resulted in higher coulombic efficiencies, the long-term stability of the deposited lithium remains a concern, with reports indicating that lithium deposits still lose stability over time.

Research indicates that using organic solvents, including benzene, in lithium melts can further refine the plating process. However, maintaining the bright and stable appearance of lithium anodes continues to require careful management of the electrolyte's acidity. Insights from various studies reveal that optimizing the electrolyte composition can yield improvements in plating/stripping efficiencies, yet the quest for a more stable and effective electrolyte additive persists.

Despite progress, there are still technical challenges in identifying the best additives to enhance lithium-ion battery performance. While some additives show promise in improving cycling stability and efficiency, the overall shelf life of plated lithium remains inadequate, highlighting the need for ongoing research in this field. The pursuit of better electrolyte formulations continues to be essential as the demand for efficient and durable energy storage solutions grows.