Li-ion batteries (LIBs), the dominant electrochemical energy storage technology in the marketplace, are nevertheless not a good candidate for grid energy storage because of their high cost. In this sense, K-ion batteries (KIBs) have emerged as a reliable alternative to LIBs in grid energy storage because potassium is earth-abundant and cost-effective. [3][4][5][6][7] In addition, potassium has a similar standard electrode potential to lithium (K + /K vs Li + /Li: −2.93 vs −3.04 V against the standard hydrogen electrode, SHE), indicating that KIBs have high energy density. [6] Moreover, potassium has similar chemical properties to lithium, making it possible for the commercialized anode materials of LIBs, graphite, to be used directly for KIBs. Unfortunately, graphite only delivers a low theoretical capacity of 279 mAh g −1 for K + intercalation by forming KC 8 due to the sizeable K + radius (K + vs Li + : 1.38 vs 0.76 Å) and sluggish K + diffusion. [7,8] In this circumstance, developing advanced KIB anode materials with high capacity and favorable K + diffusion remains a significant challenge. Recently, transition metal dichalcogenides, such as oxides, [9] sulfides, [10][11][12][13][14][15] selenides, [16,17] and tellurides, [18][19][20][21][22] have been proposed for K + storage because they have high theoretical capacities. Compared to the oxide, sulfide, and selenide counterparts, transition metal tellurides (TMTs) exhibit several appealing advantages: higher conductivity for quick electron mobility, larger lattice spacings for enhanced K + diffusion, higher density for improved volumetric capacities, and metallic thermal conductivity for adequate joule heat transport during cycling. [23] These merits make TMTs an attractive and emerging candidate for K + storage. To date, several TMTs have been reported as KIB anode materials, including CoTe 2 , Bi 2 Te 3 , MoTe 2 , and WTe 2 . [18][19][20][21]24] However, two critical limitations hinder their practical implementations. The primary one is that they are not thermodynamically favorable for reacting with K + . Table S1 (Supporting Information) lists various metal−tellurium (MT) bonds and their dissociation energies. Most of the reported TMTs have large bond dissociation energies (>200 kJ mol −1 ), indicating that more energy is needed to break the MT bonds
