Improving the interfacial stability of Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ cathode and Li metal anode via dual electrolyte additives synergistic effect

The application of Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ (LMNCO) cathode and Li anode in high specific energy batteries is impeded by particle cracking and electrode–electrolyte side reactions. Here, lithium bis(oxalate)borate (LiBOB) and dopamine (DA) are used as dual electrolyte additives to effectively stabilize the LMNCO cathode and Li anode. Specifically, LiBOB is preferentially reduced on the Li anode to participate in the formation of a B-rich inorganic solid electrolyte interface film, which suppresses the interfacial reactions between Li anode and the electrolyte. Meanwhile, DA is preferentially oxidized on the LMNCO cathode to form a thin and uniform cathode electrolyte interface film, which is beneficial to inhibit the decomposition of the electrolyte and reduce the corrosion of the LMNCO cathode. The facts are consistent with the results of density function theory. The synergetic effect of LiBOB and DA results in excellent electrochemical performance. Especially at 1 C, the capacity retention of the cell with the reference electrolyte is only 74.7% after 100 cycles, while the cell with dual-additive electrolyte is up to 92.6% after 400 cycles. This work provides a new idea to improve the electrochemical performance of Li anode and LMNCO cathode by functional electrolyte additives.