context: To further analyze the electrochemical difference between the pristine and treated LMO, the initial cycle curves for the two samples are plotted together in Fig. 2a. For pristine LMO, the plateau above 4.5 V appears as the typical behavior of the Li-rich cathode, which corresponds to the delithiation, charge compensation and oxygen release process. Upon discharge, an S-shaped curve was observed with a discharge capacity of around 200 mA h g−1. Interestingly, the characteristic charge plateau (above 4.5 V) was shortened in the T-LMO sample. Simultaneously, plateaus appeared at around 4.1 V for the charged state and 4.0 V/2.8 V for the discharged state, which can be seen clearly in the dQ/dV plots (Fig. 2b), indicating that the spinel phase may exist in T-LMO.
answer: Li-rich