Favorable Electrochemical Performance of LiMn₂O₄/LiFePO₄ Composite Electrodes Attributed to Composite Solid...

Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP)-PEO composite electrolytes are unstable in LiMn₂O₄. In addition, the discharge platform potential (2.8 and 4.0 V) difference of LiMn₂O₄ is relatively large, whereas the discharge platform potential (3.5 V) of LiFePO₄ is between 2.8 and 4.0 V. Thus, LiMn₂O₄ and LiFePO₄ can be compounded together to reduce the material platform voltage difference and obtain the advantages of both materials at the same time. Here, LiMn₂O₄/LiFePO₄ composite cathodes were applied in solid-state batteries. LAGP-PEO(LiTFSI) was used as the electrolyte. The Li/composite cathode battery using composite electrolytes has a reversible capacity of 192.8 mAh g^-1 at 50 °C and 0.1 C. It possesses favorable rate performance and exhibits very good cycling stability. In addition, the composite electrolytes can prevent the further occurrence of the Jahn-Teller effect. Meanwhile, the charge-transfer resistance slightly decreases in 10 cycles. The excellent capacity retention of the battery is connected with the excellent electrochemical stability and the well-interfaced contacts of the composite electrolytes with electrodes.