Dual carbon engineering enabling 1T/2H MoS2 with ultrastable potassium ion storage performance

Abstract

Potassium-ion batteries (PIBs) as a promising and low-cost battery technology offer the advantage of utilizing abundant and cost-effective K-salt sources. However, the effective adoption of PIBs necessitates the identification of suitable electrode materials. The 1T phase of MoS₂ exhibits enhanced electronic conductivity and greater interlayer spacing compared to the 2H phase, leading to a capable potassium ion storage ability. Herein, we fabricated dual carbon engineered 1T/2H MoS₂via a secure and straightforward ammonia-assisted hydrothermal method. The 1T/2H MoS₂@rGO@C structure demonstrated an expanded interlayer spacing (9.3 Å). Additionally, the sandwich-like structural design not only enhanced material conductivity but also effectively curbed the agglomeration of nanosheets. Remarkably, 1T/2H MoS₂@rGO@C exhibited impressive potassium storage ability, delivering capacities of 351.0 mA h g⁻¹ at 100 mA g⁻¹ and 233.8 mA h g⁻¹ at 1000 mA g⁻¹ following 100 and 1000 cycles, respectively. Moreover, the construction of a K-ion full cell was successfully achieved, utilizing perylene tetracarboxylic dianhydride (PTCDA) as the cathode, and manifesting a capacity of 294.3 mA h g⁻¹ at 100 mA g⁻¹ after 160 cycles. This underscores the substantial potential of employing the 1T/2H MoS₂@rGO@C electrode material for PIBs.