Irreversible capacity loss in additive-free Ni metal organic framework-derived hollow NiO/Ni nanocomposite electrodes as a testbed for energy storage applications

Abstract

We, for the first time, fabricated an additive-free Ni-metal organic frameworks (MOFs)-derived NiO/Ni nanocomposite Li-ion battery electrode and probed the intrinsic electrochemical properties, including charge transfer resistance and Li-ion diffusivity during the charging/discharging process. Its specific capacity within the first five cycles showed a capacity of higher than the theoretical specific capacity of NiO (718 mAh/g), which is far greater than that of a conventional slurry-based electrode. We found that, after the 1st cycle where the solid electrolyte interphase layer is formed, the Li-ion diffusivity significantly increased while the charge transfer resistance increased, indicating that the interfacial electrochemical charge transfer resistance associated with electrical conductivity within the electrode led to an initial irreversible capacity loss. We demonstrate that the additive-free system can be applied to probe intrinsic electrochemical properties, serving as an experimental testbed to elucidate the origin of irreversible capacity loss.