Synthesis of KVPO₄F/Carbon Porous Single Crystalline Nanoplates for High-Rate Potassium-Ion Batteries

Abstract

With high theoretical capacity and operating voltage, KVPO 4 F is a potential high energy density cathode material for potassium-ion batteries. However, its performance is usually limited by F loss, poor electronic conductivity, and unsteady electrode/electrolyte interface. Herein, a simple one-step sintering process is developed, where vanadium−oxalate−phosphite/phosphate frameworks and fluorinated polymer are used to synthesize carbon-coated KVPO 4 F nanoplates. It is found that the V−F−C bond generated by fluorinated-polymer-derived carbon at the interface of KVPO 4 F/C nanoplates diminishes the F loss, as well as enhances K-ions migration ability and the electronic conductivity of KVPO 4 F. The as-synthesized KVPO 4 F/C cathode delivers a reversible capacity of 106.5 mAh g −1 at 0.2 C, a high working voltage of 4.28 V, and a rate capability with capacity of 73.8 mAh g −1 at the ultrahigh current density of 100 C. In addition, a KVPO 4 F/C//soft carbon full cell exhibits a high energy density of 235.5 Wh kg −1 .

Formation of Mn–Ni Prussian Blue Analogue Spheres as a Superior Cathode Material for Potassium-Ion Batteries

“…Compared with LIBs, potassium-ion batteries (PIBs) have attracted extensive attention from researchers recently on account of their low cost and wide distribution. − The most significant merit of PIBs is the negative potential of K/K + (−2.93 V vs standard hydrogen electrode (SHE)), lower than that of Na/Na + (−2.71 V vs SHE). , Moreover, graphitic carbon (a widely used anode material in LIBs) can be employed in PIBs but cannot be used in sodium-ion batteries (SIBs) . Therefore, though it is difficult to find electrode materials for large K + , a series of materials have been designed for PIBs. − …”

Cross-Linking Network of Soft–Rigid Dual Chains to Effectively Suppress Volume Change of Silicon Anode

“…Additionally, the electrode with PAA-SS possesses the smallest pore size distribution, although they all present as homogeneous and porous. Combining these observations with the cross-sectional SEM images of the as-prepared Si electrodes from Figures S12 and S13, we could further demonstrate that the PAA-SS based Si electrode has the largest electrode density of 0.63 g/cm 3 among the three Si electrodes with different binders. After 1000 cycles at a current of 4.2 A/g, the surface of the PVDF based Si electrode became compact but consisted of plenty of microcracks (Figure 5b,c).…”

“…Developing high-capacity electrode materials is extensively considered as the key to meet the ever-growing demand for energy storage and conversion devices with high energy density. − Among the anode materials, naturally abundant silicon stands out as a promising candidate owing to its ultrahigh theoretical capacity of 4200 mAh/g. − However, issues like poor ion and electron conductivity of Si particles, pulverization of active materials, electrical contact loss, uncontrollable growth of solid electrolyte interphase (SEI) caused by the massive volume change during lithiation-delithiation processes, and subsequent inferior cycling reversibility severely impede its widespread industrial applications . To address these issues, great efforts have been devoted to structural engineering of Si based materials or designing polymer binders with strong adhesion and excellent mechanical strength.…”

Electrolyte Regulation for Non-Graphitic Carbon to Achieve Stable Long-Cycling K-Storage

“…The development of lithium-ion batteries with high energy density and long cycle life is of significance to electric vehicles and portable electronic devices (such as mobile phones and notebook computers). However, accusing to low lithium concentration (0.0017 wt %) and unequal distribution in the earth’s crust, extensive focus has redirected to potassium-ion batteries (PIBs) and sodium-ion batteries (SIBs), which have higher elemental abundance (K: 2.1 wt %, Na: 2.3 wt %). − In comparison to SIBs, PIBs exhibit higher energy density and faster K + migration rate in electrolyte, attributing to a lower standard K + /K potential of −2.93 V (vs −2.71 V of Na + /Na) and smaller K + stokes radius in electrolytes. , Furthermore, the significant advantage in cost reduction of PIBs guaranteed by the relatively inexpensive potassium salt has resulted in considerable industrial superiority, establishing PIBs as a promising next-generation energy storage technology for extensive applications.…”

“…1−4 In comparison to SIBs, PIBs exhibit higher energy density and faster K + migration rate in electrolyte, attributing to a lower standard K + /K potential of −2.93 V (vs −2.71 V of Na + /Na) and smaller K + stokes radius in electrolytes. 5,6 Furthermore, the significant advantage in cost reduction of PIBs guaranteed by the relatively inexpensive potassium salt has resulted in considerable industrial superiority, 7 establishing PIBs as a promising next-generation energy storage technology for extensive applications.…”