Lithium-oxygen battery has the highest theoretic energy density among all rechargeable batteries. But its discharge product Li₂O₂ is difficult to be oxidized back in the charge process because it is difficult to transfer electron from Li₂O₂ to the cathode material (mostly carbon). Here, we introduce 3 strategies to facilitate the electron transfer during charging process: 1. To use redox mediators as redox shuttles between carbon and Li₂O₂; 2. To use electrolyte which can dissolve Li₂O₂ (or other peroxide species) so that the dissolved Li₂O₂ can be oxidized at the carbon surface; 3. To use some highly elastic polymer network to push the Li₂O₂ to the carbon surface, so that the carbon-Li₂O₂ contact can be improved. The third strategy was firstly developed in our group and is very suitable to make high loading thick air cathodes with areal capacity > 12 mAh cm^-2. These methods were all found to be effective, but not perfect. Especially when the Li metal anode problems are considered. The pros and cons of these strategies will be exhibited, compared and explained. It is also possible to combine these strategies with other advanced cathode architectures and catalysts to further improve the performance. Our study is helpful to design high energy density Li-O₂ prototype cells with REAL reversibility.

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