Layered Potassium Titanium Niobate/Reduced Graphene Oxide Nanocomposite as a Potassium-Ion Battery Anode

Abstract

With graphite currently leading as the most viable anode for potassium-ion batteries (KIBs), other materials have been left relatively under-examined. Transition metal oxides are among these, with many positive attributes such as synthetic maturity, long-term cycling stability and fast redox kinetics. Therefore, to address this research deficiency we report herein a layered potassium titanium niobate KTiNbO5 (KTNO) and its rGO nanocomposite (KTNO/rGO) synthesised via solvothermal methods as a high-performance anode for KIBs. Through effective distribution across the electrically conductive rGO, the electrochemical performance of the KTNO nanoparticles was enhanced. The potassium storage performance of the KTNO/rGO was demonstrated by its first charge capacity of 128.1 mAh g−1 and reversible capacity of 97.5 mAh g−1 after 500 cycles at 20 mA g−1, retaining 76.1% of the initial capacity, with an exceptional rate performance of 54.2 mAh g−1 at 1 A g−1. Furthermore, to investigate the attributes of KTNO in-situ XRD was performed, indicating a low-strain material. Ex-situ X-ray photoelectron spectra further investigated the mechanism of charge storage, with the titanium showing greater redox reversibility than the niobium. This work suggests this low-strain nature is a highly advantageous property and well worth regarding KTNO as a promising anode for future high-performance KIBs.

Dual-Defect Engineering Strategy Enables High-Durability Rechargeable Magnesium-Metal Batteries

“…According to the Raman analysis (Fig. S7), the signal intensity ratio of sp 2 graphite carbon (D band) and sp 3 disordered carbon (G band) in MVOH/rGO ( I D / I G = 1.14) is significantly higher than that in GO ( I D / I G = 0.8), implying that the deoxidization of GO is realized by the redox reaction between carboxyl groups in GO and V 5+ [ 41 , 44 ]. This is verified by the gas bubbles being observed after the hydrothermal synthesis of MVOH/rGO, which are attributed to the CO 2 gas produced by the oxidation of carboxyl groups in GO.…”

Recent advances in rational design for high-performance potassium-ion batteries

“…have received much attention due to their high capacity, natural abundance, and environmental benignity. 547–550 However, the application of metal oxide anode materials in PIBs still faces the following challenges: (1) the volume changes greatly when the conversion reaction occurs with K + , resulting in severe extrusion of the electrode and loss of collector contact; (2) the ion and electronic conductivity is poor, resulting in a low ion diffusion coefficient and high resistance; and (3) the SEI is unstable and ICE is low. 346,551 To overcome these shortcomings, commonly used tools include nanofabrication, carbon coating, and surface engineering.…”

Enhancing reversible Na-ion intercalation by introducing K-ions into layered vanadyl phosphate for sodium-ion battery cathodes

“…Utilizing the knowledge gained from our and other groups' exploration of materials for potassium-ion batteries (PIBs) [23][24][25][26][27][28][29][30][31], K-containing layer-structured materials exhibit reversible K intercalation due to the larger interlayer spacings compared to their Na-containing counterparts, but they are usually formed with a lower K + content [32]. This is likely due to the strong K + -K + repulsion in the interlayer space and consequently, not every site in the interlayer space can be occupied by the large sized K + [33].…”