Electrolyte‐Mediated Stabilization of High‐Capacity Micro‐Sized Antimony Anodes for Potassium‐Ion Batteries

Abstract

The attractive features of KIBs include abundant potassium sources, and K + /K redox potential that is close to Li + / Li (−2.93 V vs −3.04 V) and even lower than −2.71 V of Na + /Na. [2] Therefore, KIBs have the potential to provide greater energy density at a lower cost. However, designing high capacity, stable, and safe electrodes for KIBs remains challenging. This is because the ionic radius of potassium (K +) is large, which can cause a low specific capacity and degrade stability of the electrode during the K + (de-)intercalation or reaction. [3] Although many kinds of cathodes with a large crystalline channel or durable conjugated structure (e.g., metal layered oxide, [4] polyanionic compound, [5] Prussian blue analogs, [6] organic materials [7]) are being hitherto developed, most reported capacities have been less than 150 mAh g-1. This low capacity of the cathodes presents a serious bottleneck for KIB development. [8] Alternatively, various high capacity anodes such as alloys, [9] transition-metal oxides/sulfides, [10] and MXene-based materials [11] bring new opportunities to design high-energy-density KIBs. Particularly, the alloying anodes can exhibit significantly higher capacity than classic carbon-based anodes (i.e., 280 mAh g-1 of graphite). [12] For example, the potassium storage capacity of metallic antimony (Sb) can reach as high as 660 mAh g-1 , which is close to the theoretical capacity of metal K (i.e., 687 mAh g-1). [13] But, the capacity suffers a severe capacity decay caused by the large volumetric change of Sb (≈300%). [9a] Although a variety of strategies including structural design (e.g., nanoparticles, [14] hollow spheres, [15] fibers, [9a] films, [13] and hierarchical structures [16]), carbon modification (e.g., Sb@NC, [17] Sb@CNFs, [13] Sb@Go, [18] Sb@CSN, [19] and Sb/C [20]), and SEI engineering [19] are being developed to stabilize the Sb anode, the capacity and stability still have a large room to be improved. Herein, we present a new approach of electrolyte engineering to stabilize bulk Sb anodes. Extremely high capacity of 628 mAh g-1 at the current density of 100 mA g-1 and a good rate capability of 305 mAh g-1 at the hash current density of 3 A g-1 can be achieved by varying the electrolyte composition (e.g., anions, solvent, and concentration). To our knowledge, this is the best electrochemical performance reported so far for Sb alloying anode in KIBs. Amazingly, this high capacity which remained stable for over 200 cycles, was achieved without the need for Alloying anodes exhibit very high capacity when used in potassium-ion batteries, but their severe capacity fading hinders their practical applications. The failure mechanism has traditionally been attributed to the large volumetric change and/or their fragile solid electrolyte interphase. Herein, it is reported that an antimony (Sb) alloying anode, even in bulk form, can be stabilized readily by electrolyte engineering. The Sb anode delivers an extremely high capacity of 628 and 305 mAh g-1 at current densities of 100 and 3...

Recent advances in anode materials for potassium-ion batteries: A review

“…Unfortunately, Sb suffers from significant volume expansion (~ 390%) during electrochemical processes, leading to serious aggregation and pulverization of electrode materials, which deteriorates the electrochemical performances [103,104]. To resolve the above challenges, the construction of nanostructured Sb/carbon or Sb/MXene composites has been widely recognized as an effective and straightforward strategy [105][106][107][108][109][110]. The nanostructured Sb can release the stress stemming from volume variations, while the carbon matrix/MXene sheets not only buffer the volume changes but also ensure the continuous electrical networks.…”

Growth Mechanism of Micro/Nano Metal Dendrites and Cumulative Strategies for Countering Its Impacts in Metal Ion Batteries: A Review

“…Polyaspartic acid-linked SnS2 2D nanostructures encapsulated into an Ndoped hollow carbon network provide an inflated interlamellar gap and accelerate ionic transport channels with autonomous dendrite crackdown [404]. Antimony, bismuth, and P block element-based metal alloys also offer high capacity with a dendrite-free SEI [452]. Microporous scaffolds with conjugated polymers and tunable properties have shown enhanced performance [453].…”

Recent Developments of Antimony-Based Anodes for Sodium- and Potassium-Ion Batteries

“…Due to the similar reaction mechanism of PIBs and SIBs and the similar ionic radius of K + and Na + , many modification strategies for Sb-based materials (e.g., metal Sb, oxide, sulfide, selenide, and alloy) have been used to enhance their performance as the anodes of PIBs. However, the Sb-based materials have encountered obstacles as an anode in PIBs that are similar to those of SIBs; these obstacles can be overcome by several classic strategies, such as coupling carbon material, introducing heteroatom dopants, combining with other conductive substrates, synthesizing specific structures, and employing specific electrolytes and binders [131][132][133][134][135][136][137][138][139][140][141][142][143][144][145].…”

“…As presented in Fig. 12b, Zhou et al [143] improved the K-storage ability of Sb alloy via electrolyte engineering. The electrolyte composition (anion, solvent, concentration, etc.)…”

“…Reproduced with permission from Ref. [143]. Copyright 2021, John Wiley & Sons, Inc resulted in an excellent performance.…”