•We succeeded in suppressing the power fade using mechano-chemical bonding technology.•Crack formation of NCM correlated with the ASI (10 s) increase.•Coating with Al2O3 can be an effective technique for improving the power fade.LiNi1/3Co1/3Mn1/3O2 particles were coated with Al2O3 nanoparticles by means of a mechanochemical bonding process; SEM confirmed that the Al2O3 particles were uniformly coated over the surface of the LiNi1/3Co1/3Mn1/3O2 powder. During subsequent electrochemical testing using pouch cells, uncoated LiNi1/3Co1/3Mn1/3O2 exhibited a gradual capacity fading and an increase in area specific impedance (ASI) at a 50% state of charge. Under the same conditions, the increase in ASI of the Al2O3 modified samples was significantly suppressed, although the initial performance (charge/discharge capacity and ASI) slightly deteriorated. The Al2O3 coating was also effective in improving the cyclability of LiNi1/3Co1/3Mn1/3O2 at elevated temperatures by reducing the extent of cracking.

Room temperature ionic liquids (RTILs) were applied to a lithium (Li) metal battery system, and the behavior of Li electrodeposition on nickel electrodes in RTILs was investigated using in situ optical microscopy with/without an organic additive, vinylene carbonate (VC), in the RTILs. Two RTILs, PP13[TFSA] (N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)amide) and EMI[FSA] (1-ethyl-3-methylimidazolium bis(fluorosulfonyl)amide), were chosen as the base electrolytes. Dendritic particles were obtained in the case of EMI[FSA] with and without VC, and PP13[TFSA] without VC, while non-dendritic fine particles were obtained in the case of PP13[TFSA] with VC.