SnCo Nanoalloy/Graphene Anode Constructed by Microfluidic-Assisted Nanoprecipitation for Potassium-Ion Batteries

Abstract

Potassium-ion batteries have attracted substantial interest due to abundant resources and comparable electrochemical performance with lithium-ion batteries. Although plenty of graphene-based materials with ultrahigh performance have been designed, in practice, the dendrite growth induced by the capacitive-dominated potassium storage mechanism and the poor repeatability resulting from the complicated process are worrisome. To address these issues, it is envisaged that embedding SnCo nanoalloys in a graphene nanosheet matrix (SnCo NAs/G) can be an effective strategy for the following two reasons: (1) The embedded SnCo NAs are responsible for expanding the interlayer space and facilitating the potassium-ion diffusion in a graphene nanosheet matrix and (2) the combination of the microfluidic technology and the organic molecule confinement reaction endows the repeatability and large-scale production. As a result, the SnCo NAs/G-L anode is prepared with a low content of SnCo NAs (9.16 wt %). It shows advantages in the electrochemical performance as compared to the graphite anode. A reversible specific capacity of 165 mA h g–1 at 50 mA g–1 over 100 cycles is exhibited by SnCo NAs/G-L. It has a retention capacity of 179 mA h g–1, that is, 78.8% is recovered after charging at 500 mA g–1. Moreover, the intercalation reaction as the dominant potassium storage mechanism is beneficial for avoiding the safety problems arising from potassium dendrite growth. More interestingly, graphite-based composites constructed by the microfluidic technology successfully prove the high potential for large-scale production.

Stable Solid Electrolyte Interface Achieved by Separator Surface Modification for High-Performance Anode-free Potassium Metal Batteries

“…The rGO coating layer has the following advantages: (1) The purpose of inhibiting K dendrite is achieved by guiding the uniform deposition of K + ; (2) The contact between K metal and rGO coating leads to the formation of a KF-rich SEI on the surface of Cu foil, which contributes to the uniform distribution of K + solvents, inhibits the "tip effect", and stabilizes the deposition of K + ; (3) The K-storage SEI can also be used as a soft host storage of K during long-term cycling.…”

“…Potassium and sodium ion batteries are attractive because of their low redox potentials, high energy densities, and abundant resources (compared with lithium). − The design of high load and high energy density electrodes is helpful to promote their development and application. − In addition, potassium metal anodes with a lower cost, lower redox potential, and higher abundance are more likely to be used in high power grid energy storage systems. − Unfortunately, the practical application of K metal batteries (KMBs) is restricted by some complex issues. First, the higher chemical activity between K metal and electrolytes as well as the larger volume change during potassium plating/stripping will inevitably lead to the formation of an unstable solid electrolyte interface (SEI) during charge/discharge processes. − In addition, uneven deposition of potassium ions (K + ) will lead to uncontrollable K dendrite formation. , These factors inevitably lead to the low Coulombic efficiency (CE), poor cycle performance, and weak rate performance of K metal anodes …”

Alloying and Nanotechnology for Sn‐based Anode Materials: Paving the Way to the Future of Lithium‐Ion Batteries

“…[160][161][162][163][164] Furthermore, the transformation of SnCo(OH) 6 into SnÀ Co alloy can be achieved by adjusting the pH value of the Co and Sn salt solution. [165][166][167][168] The microfluidic-assisted coprecipitation systems have demonstrated the effective synthesis of SnCo(OH) 6 nanoparticles. [115] Copyright (2016) with permission from Royal Society of Chemistry.…”

“…Technologies such as mechanochemical synthesis, [55,120] aerosol spray pyrolysis, [133,145] P-milling, [115,131] severe plastic deformation, [101] and microfluidicassisted synthesis should be further explored and given more attention due to their potential for scaling up production while ensuring desired material properties. [168] In summary, considering the scalability and feasibility of the preparation processes is vital for the successful commercialization of Sn-based anodes. Advances in large-scale MOF production, pH adjustment techniques, and the development of PECVD systems for 3D graphene materials contribute to the potential practical applications of Sn-based anodes.…”

“…Thus, large‐scale production processes and continuous flow chemistry techniques for the preparation of MOFs have been developed [160–164] . Furthermore, the transformation of SnCo(OH) 6 into Sn−Co alloy can be achieved by adjusting the pH value of the Co and Sn salt solution [165–168] . The microfluidic‐assisted coprecipitation systems have demonstrated the effective synthesis of SnCo(OH) 6 nanoparticles.…”