Ultralong storage life of Li/MnO2 primary batteries using MnO2 -(CFx)nwith C-F semi-ionic bond as cathode materials

The theoretical self-discharge rate of Li/MnO2 primary batteries is less than 1% per year, but the actual self-discharge rate is similar to 8% per year, and the shelf life of the coin batteries (such as CR2016) is only 5 years. In this paper, MnO2 mixed some (CFx)(n) as cathode material in Li/MnO2 primary batteries, not only can effectively reduce self-discharge rate, but also improve capacity density and heighten discharge plateau voltageafter storage. After storage at 25 degrees C for 60 days, the specific charge capacity of Mn0 2 decreases from 293 mAh g(-1) to 283 mAh g(-1), while MnO2-(CFx)(n) increases from 312 mAh g(-1) to 326 mAh g(-1). After storage for 30 days at 45 degrees C, the self-discharge rates of MnO2 and MnO2-(CFx)(n) are 9.21% and 1.92% (0.5 mA cm(-2)), respectively. During storage and the initial stage of discharge, F in MnO2 -(CFx)(n) can act on Mn-O bond and some C-F semi-ionic bonds form when Li+ insert into (CFx)(n) layers, these change the unit cell parameters of MnO2 and the utilization of MnO2 increases. (C) 2019 Elsevier Ltd. All rights reserved.