Potassium‐Ion Battery Anode Materials Operating through the Alloying–Dealloying Reaction Mechanism

Abstract

Anode materials that operate via the alloying–dealloying reaction mechanism are well known in established and maturing battery systems such as lithium‐ion and sodium‐ion batteries. Recently, a new type of metal‐ion battery that utilizes K+ ions in its operating principle has attracted significant attention due to a possibility of building high voltage cells using an abundant potassium ionic shuttle. Establishing promising electrode materials is of paramount importance for this new type of battery. This feature article summarizes available early results on the alloying–dealloying anode materials in potassium electrochemical cells. Based on original research (some data are presented for the first time) and independently published literature, experimental results on silicon, tin, phosphorus, antimony, and lead‐containing anodes are critically discussed. The electrochemical properties, charge storage mechanisms, and achievable capacities are considered. The results are compared with the behaviors of the same materials in lithium and sodium cells, and the importance of the volumetric parameters of electrodes is emphasized. Finally, a number of further research directions in these interesting anode materials are suggested. The feature article provides a useful reference for the growing number of researchers and specialists working in the field of emerging metal‐ion batteries with non‐lithium chemistries.

Sodium/Potassium‐Ion Batteries: Boosting the Rate Capability and Cycle Life by Combining Morphology, Defect and Structure Engineering

“…This outperforms other carbon‐based anodes reported so far for SIBs in the literature (Figure d) . Table S1 in the Supporting Information compares the cycle life and stability of the N‐CNS electrode with other carbon‐based electrodes from the literature . One can see that the N‐CNS electrode shows the best cycling stability for SIBs compared to other carbon‐based ones.…”

“…Compared to cathode materials, anode materials determine the full cell performance of both SIBs and PIBs . The commonly employed anode materials are based on either carbon, alloy or conversion‐type materials . The latter two correspond to high theoretical capacity but poor cyclability.…”

Advancements and Challenges in Potassium Ion Batteries: A Comprehensive Review

“…where A is an alloying element, M is an alkali element (e.g., Li, Na, K), x and y are the stoichiometric coefficients for the chemical formula of the final alloy. At the lower voltages, various intermediate alloy compositions are possible between the de‐alloyed state and the final alloy state . The occurrence of intermediate compounds during the reaction process often alters the shape of the charge/discharge curve of the material, generally containing plateaus and slopes .…”

“…Theoretically, many elements can form a reversible alloy with K, but more experimental evidences are required to support this statement . For instance, Si can form KSi alloy, but it could not show any redox activity in organic electrolyte‐based KIBs . A recent study investigated the various alloying reaction steps of Sn 4 P 3 during the potassiation/depotassiation process ( Figure a).…”

Nature of Bimetallic Oxide Sb2MoO6/rGO Anode for High‐Performance Potassium‐Ion Batteries

“…However, in comparison with the smaller lithium ions (a radius of 0.76 Å), the large-sized potassium ions (a radius of 1.38 Å) could arouse a severe volume change of the electrode material during charge/discharge, seriously weakening the electrode stability and resulting in an unsatisfied battery performance. [34,35] For example, antimony oxide (Sb 2 O 3 ) possesses a theoretical capacity as high as 1103 mAh g −1 for KIBs through both conversion reactions and alloy reactions. which are being explored vigorously but yield a relatively low specific capacity, [17][18][19][20][21][22][23][24][25][26][27] metal oxides, such as iron oxides, [28] molybdenum oxides, [29,30] niobium pentoxides, [31] tin oxides, [32] and titanium oxides, [33] are interesting anode candidates considering their high gravimetric and volumetric specific capacity, which are able to provide high performance anodes for KIBs.…”