Solvation‐Mediated Free Energy Stabilization Enables Li/CF x Pouch Cells Over 800 Wh kg −1 via Minimizing Heat Dissipation

ABSTRACT Maximizing electrochemical energy conversion efficiency requires minimizing parasitic heat release. Li/CF x batteries, despite their high theoretical energy density (>2100 Wh kg −1 ), suffer from severe voltage loss and thermal accumulation that compromise both performance and safety. Here, we identify that parasitic decomposition of a metastable intermediate phase (C[F – ·Li + ·Sol n ]) constitutes the primary energy loss pathway that dissipates chemical energy as heat instead of electricity. By introducing a solvation‐mediated Gibbs free energy stabilization strategy via strengthening the Li + –solvent interaction, we delay the premature decomposition of C[F – ·Li + ·Sol n ] intermediate and promote the conversion of chemical energy to electrical output. This approach reduces heat generation by 39.6% and elevates the discharge voltage from 2.50–2.92 V. Practical multi‐ampere‐hour pouch cells (6–20 Ah) achieve stable discharge plateaus near 2.90 V and record cell‐level energy densities of 816–830 Wh kg − 1 . This work establishes a thermodynamic paradigm of solvation‐mediated free‐energy tuning for high‐energy‐density Li/CF x battery technologies.