A team at MIT has introduced a new model that explains the rates of lithium intercalation in lithium-ion batteries, which is crucial for improving battery performance. The research indicates that lithium intercalation is governed by a process called coupled ion-electron transfer, where lithium ions and electrons move simultaneously into the electrode. This model contrasts with the traditional Butler-Volmer equation, which has proven inconsistent in predicting intercalation rates. By measuring rates across various materials, the researchers found that altering electrolyte compositions can enhance reaction efficiency. Their findings could lead to the design of batteries that charge faster and last longer, providing a theoretical framework for future innovations in battery technology.