Toward the High‐Performance Lithium Primary Batteries by Chemically Modified Fluorinate Carbon with δ‐MnO2

Li/CFx battery is one of the most promising lithium primary batteries (LPBs) which yields the highest energy density but with poor rate capability. This Achilles'' heel hinders the large-scale applications of Li/CFx batteries. This work first reports a facile chemical modification method of CFx with δ-MnO2 . Having benefited from the chemical bonding, the electrochemical performance at high-rate discharge is remarkably enhanced without compromising the specific capacity. The coin cells exhibit an energy density of 1.94 × 103 Wh kg-1 at 0.2 C, which is approaching the theoretical energy density of commercial fluorinated graphite (2.07 × 103 Wh kg-1 ). A power density of 5.49 × 104 W kg-1 at 40 C associated with an energy density of 4.39 × 102 Wh kg-1 , which is among the highest value of Li/CFx batteries, are obtained. Besides, the punch batteries achieve an ultrahigh power density of 4.39 × 104 W kg-1 with an energy density of 7.60 × 102 Wh kg-1 at 30 C. The intrinsic reasons for this outstanding electrochemical performance, which are known as the fast Li+ diffusion kinetics guided by thin δ-MnO2 flakes and the low formation energy barrier caused by chemical bonding, are explored by the galvanostatic intermittent titration technique (GITT) and theoretical calculations.