Fig. 4. Thermal and structural stability of Gr-coated NCA cathodes.

a Discharge capacity of the Gr-coated electrode (φ = 99.5:0:0.5/ρ ~3.9 g cm⁻³) and bare electrode (φ = 96:2:2/ρ ~3.3 g cm⁻³), measured at 30 °C in the voltage range of 2.75–4.5 V vs. Li⁺/Li at a current rate of 0.5 C. b–d Thermal stability tests of Gr-coated and bare electrodes subjected to charging to 4.3 V vs. Li⁺/Li. b Content of TM ions dissolved from the electrodes immersed in the electrolyte for one week at 60 °C. c DSC profiles. d Pressure changes measured using a gas-cell system at 60 °C. For reference, an empty cell and electrolyte-containing cell without any electrode are examined.