Stabilizing potassium ion batteries with RGO coated cathode architectures

• RGO coating on SKNMCO cathode was achieved via a hydrothermal route. • The X-ray diffraction profile of RGO-SKNMCO corresponds to the R 3 m space group. • RGO-SKNMCO shows 0.56 nm spacing and RGO layer thickness of 15–20 nm. • It delivers a superior initial capacity approximately104 mAh g -1 at C/10. • The capacity retention is approximately 71 % after 100 cycles. Potassium-ion batteries (KIBs) have gained significant attention as a promising alternative to lithium-ion batteries, owing abundance of resources, high ionic conductivity in electrolytes, and its low standard redox potential. Despite these advantages, the widespread commercialization of KIBs is challenged by the scarcity of cathode materials capable of maintaining structural integrity during the repeated insertion and extraction of large-sized K + ions. In this study, a cathode material is synthesized via a solid-state method, and its structural stability is enhanced through surface modification with reduced graphene oxide (RGO) using a hydrothermal technique. The RGO coating establishes a continuous conductive framework that facilitates efficient ion transport and serves as a protective barrier, minimizing direct contact between the cathode and the electrolyte. This protective layer also contributes to the reduction of interfacial charge transfer resistance. Consequently, the RGO-coated RGO-SKNMCO delivers superior electrochemical performance, characterized by improved cycling durability and overall stability. Notably, the RGO-modified cathode solid-state synthesized K 0.67 Ni 0.3 Mn 0.6 Co 0.1 O 2 (RGO-SKNMCO) exhibits enhanced capacity sample achieves a maximum discharge capacity of approximately 104 mAh g -1 at 0.1C and retains about 71% of its capacity after 100 cycles at 0.2C.