Toward the High-Performance Lithium Primary Batteries by Chemically Modified Fluorinate Carbon with d-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 d-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 x 10(3) Wh kg(-1) at 0.2 C, which is approaching the theoretical energy density of commercial fluorinated graphite (2.07 x 10(3) Wh kg(-1)). A power density of 5.49 x 10(4) W kg(-1) at 40 C associated with an energy density of 4.39 x 10(2) 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 x 10(4) W kg(-1) with an energy density of 7.60 x 10(2) 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 d-MnO2 flakes and the low formation energy barrier caused by chemical bonding, are explored by the galvanostatic intermittent titration technique (GITT) and theoretical calculations.