For pristine LMO, the Mn 2p3/2 peaks range from approximately 640.3 eV to 643.9 eV, indicating mixed Mn 2+ , Mn 3+ , and Mn 4+ oxidation states (see Figure ). After recycling, the peaks shift toward higher binding energies (642.3 eV), suggesting an increase in Mn 4+ at the surface. This indicates that Mn 3+ disproportionation occurred under aqueous conditions , leading to Mn dissolution, as confirmed by ICP-MS. Some dissolved Mn ions may have reprecipitated as Mn(OH)2 , as indicated by O 1s broadening (Figure and S9f), although oxidation remains the dominant surface transformation . The Li 1s spectrum remains unchanged (Figure ).