Li-rich cation-disordered rocksalts (DRX) represent a new class of promising high-energy Li-ion battery cathode materials. In this presentation, we systematically evaluated the effect of redox-inactive d0 transition-metal (TM) in the cationic sublattice and fluorine substitution in the anionic sublattice on the electrochemical behavior of cation disorder rock salts. It was found that, although electrochemically inactive, d⁰ TM serves as a modulator for oxygen redox, with Nb⁵⁺ significantly enhancing initial charge storage contribution from oxygen redox. Further studies using differential electrochemical mass spectroscopy and resonant inelastic X-Ray scattering reveal that Ti⁴⁺ is better in stabilizing the oxidized oxygen anions (O^n-, 0 < n < 2) in the rocksalt lattice, leading to more reversible O redox processes with less oxygen gas release. Moreover, partial fluorine (F) substitution into the oxygen sublattice have been shown to improve capacity and cycling stability of DRX cathodes.  Fluorine substitution was performed based on a Ti-based DRX (Li_1.2Ti_0.4Mn_0.4O₂) and leads to two oxyfluoride compounds with different Li/Mn ratios. Through careful comparison on chemical and structural changes upon cycling, we show that changes in TM are manifested by its chemical reduction along with the degeneration in coordination environment. The study reveals the effect of Li/Mn ratio on the degradation behavior and other critical insights needed for further development of DRX cathode materials with improved performance.