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Inducing new phases of transition metal dichalcogenides by controlling the d‐electron‐count has attracted much interest due to their novel structures and physicochemical properties. 1T" ReSe2 is a promising candidate for sodium storage, but the low electronic conductivity and limited active sites hinder its electrochemical capacity. Herein, new‐phase 1T' Re0.75V0.25Se2 crystals (P2/m) with zig‐zag chains are successfully synthesized. The 1T"‐1T' phase transition results from the electronic reorganization of 5d orbitals via electron extraction after V‐atom doping. The electrical conductivity of 1T' Re0.75V0.25Se2 is 2.7 × 105 times higher than that of 1T" ReSe2. Moreover, density functional theory (DFT) calculations reveal that 1T' Re0.75V0.25Se2 has a larger interlayer spacing, lower bonding energy, and migration energy barrier for Na+ ions than 1T" ReSe2. As a result, 1T' Re0.75V0.25Se2 electrode shows an excellent rate capability of 203 mAh g−1 at 50 C with no capacity fading over 5000 cycles for sodium storage, which is superior to most reported sodium‐ion anode materials. This 1T' Re0.75V0.25Se2 provides a new platform for various applications such as electronics, catalysis, and energy storage. [ABSTRACT FROM AUTHOR]

Abstract Inducing new phases of transition metal dichalcogenides by controlling the d‐electron‐count has attracted much interest due to their novel structures and physicochemical properties. 1T’’ ReSe2 is a promising candidate for sodium storage, but the low electronic conductivity and limited active sites hinder its electrochemical capacity. Herein, new‐phase 1T’ Re0.75V0.25Se2 crystals (P2/m) with zig‐zag chains are successfully synthesized. The 1T’’‐1T’ phase transition results from the electronic reorganization of 5d orbitals via electron extraction after V‐atom doping. The electrical conductivity of 1T’ Re0.75V0.25Se2 is 2.7 × 105 times higher than that of 1T’’ ReSe2. Moreover, density functional theory (DFT) calculations reveal that 1T’ Re0.75V0.25Se2 has a larger interlayer spacing, lower bonding energy, and migration energy barrier for Na+ ions than 1T’’ ReSe2. As a result, 1T’ Re0.75V0.25Se2 electrode shows an excellent rate capability of 203 mAh g−1 at 50 C with no capacity fading over 5000 cycles for sodium storage, which is superior to most reported sodium‐ion anode materials. This 1T’ Re0.75V0.25Se2 provides a new platform for various applications such as electronics, catalysis, and energy storage.