Ameliorating Interfacial Issues of LiNi <sub>0.5</sub> Co <sub>0.2</sub> Mn <sub>0.3</sub> O <sub>2</sub> /Poly(propylene carbonate) by Introducing Graphene Interlayer for All‐Solid‐State Lithium Batteries
Zilong Zhuang, Lezhi Yang, Bowei Ju, Gang Lei, Qian Zhou, Hanxiao Liao, Ao Yin, Zhiyuan Deng, Yating Tang, Shibiao Qin, Feiyue Tu
Abstract
Interfacial side reaction mechanism between poly(propylene carbonate) solid polymer electrolyte (PPC-SPE) and LiNi0.5Co0.2Mn0.3O2 cathode (c-NCM) is investigated. Ni3+ 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 conducive to enhance the electrochemical performance of all-solid-state lithium batteries.