Design and Optimization of Composite Cathodes for Solid-State Batteries Using Hybrid Carbon Networks with Facile Electronic and Ionic Percolation Pathways

Solid-statebatteries (SSBs) have emerged as a promisingalternativeto conventional liquid electrolyte batteries due to their potentialfor higher energy density and improved safety. However, achievinghigh performance in SSBs is difficult because of inadequate contactand interfacial reactions that generate high interfacial resistance,as well as inadequate solid-solid contact between electrodes.These chronic issues are associated with inhomogeneous ion and electrontransport networks owing to imperfect solid-solid interfacialcontact. This study developed an optimal interfacial engineering strategyto facilitate an ion-electron transport network by designingan active material (NCM622) uniformly filled with a thin layer ofa solid electrolyte (garnet-type Li6.25Ga0.25La3Zr2O12) and conductive additives.The optimal composite electrode architecture enhanced the high capacity,high rate capability, and long-term cycle stability, even at roomtemperature, owing to the percolating network for facile ionic conductionthat assured a homogeneous reaction. In addition to mitigating themechanical degradation of the cathode electrode, it also reduced thecrosstalk effects on the anode-solid electrolyte interface.Effectively optimizing the selection and use of conductive additivesin composite electrodes offers a promising approach to addressingkey performance-limiting factors in SSBs, including interfacial resistanceand solid-solid contact issues. This study underscores thecritical importance of cathode architecture design for achieving high-performanceSSBs by ensuring that the interfaces are intact with solid electrolytesat both the cathode and anode interfaces while promoting uniform reactions.This study provides valuable insights into the development of SSBswith improved performance, which could have significant implicationsfor a wide range of applications.