Ameliorating Interfacial Issues of LiNi0.5Co0.2Mn0.3O2/Poly (propylene carbonate) by Introducing Graphene Interlayer for All-Solid-State Lithium Batteries

摘要

Interfacial side reaction mechanism between poly(propylene carbonate) solid polymer electrolyte (PPC-SPE) and Li- Ni0.5Co0.2Mn0.3O2 cathode (c-NCM) is investigated. Ni 3+ and Co4+ species generated by electrochemical oxidization process can decompose poly(propylene carbonate) to aldehyde. To address this interface issue, a graphene interlayer is introduced to the LiNi0.5Co0.2Mn0.3O2 cathode surface via a facile method to improve cycle stability, rate capability and interfacial resistance. After 50 cycles at 0.3 C, the capacity retention of G@c-NCM is 97.9% and the resistance is less than 20 Ω, the improved electrochemical properties can be attributed to the graphene interlayer slows the side reaction, facilitates interfacial charge- transfer process and stabilizes the cathode structure. These results demonstrate that modifying LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode surface with graphene interlayer is con- ducive to enhance the electrochemical performance of all- solid-state lithium batteries.