Composition Engineering Boosts Voltage Windows for Advanced Sodium-Ion Batteries

Abstract

Transition-metal selenides have captured sustainable research attention in energy storage and conversion field as promising anodes for sodium-ion batteries. However, for the majority of transition metal selenides, the potential windows have to compress to 0.5–3.0 V for the maintenance of cycling and rate capability, which largely sacrifices the capacity under low voltage and impair energy density for sodium full batteries. Herein, through introducing diverse metal ions, transition-metal selenides consisted of different composition doping (CoM–Se2@NC, M = Ni, Cu, Zn) are prepared with more stable structures and higher conductivity, which exhibit superior cycling and rate properties than those of CoSe2@NC even at a wider voltage range for sodium ion batteries. In particular, Zn2+ doping demonstrates the most prominent sodium storage performance among series materials, delivering a high capacity of 474 mAh g–1 after 80 cycles at 500 mA g–1 and rate capacities of 511.4, 382.7, 372.1, 339.2, 306.8, and 291.4 mAh g–1 at current densities of 0.1, 0.5, 1.0, 1.4, 1.8, and 2.0 A g–1, respectively. The composition adjusting strategy based on metal ions doping can optimize electrochemical performances of metal selenides, offer an avenue to expand stable voltage windows, and provide a feasible approach for the construction of high specific energy sodium-ion batteries.

Bimetal‐organic Framework‐derived Co9S8/ZnS@NC Heterostructures for Superior Lithium‐ion Storage

“…The high‐resolution XPS spectra show the binding energy of Zn 2p 3/2 (1020.7 eV), Zn 2p 1/2 (1043.7 eV) in Co 9 S 8 /ZnS@NC, respectively, however, the Zn 2p 3/2 (1020.9 eV) and Zn 2p 1/2 (1043.9 eV) in the single ZnS@NC shifted toward the low beside (Figure d). Four peaks located at 778.2, 780.1, 793.2 and 796.8 eV in Co 9 S 8 /ZnS@NC with two satellite peaks at 784.5 eV and 802.2 eV were attributed to Co 2+ /Co 3+ , chemical shifts were also observed compared with single Co 9 S 8 , implying the successful constitution of heterointerfaces between the integrated Co 9 S 8 and ZnS components consistent with the results of HRTEM discussed later.…”

Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co1−xSe2/Graphene Heterostructure for Sodium‐Ion Batteries

“…Meanwhile, the Co 1− x Se 2 /GE has the lowest charge platform among all the electrodes. The high low‐voltage capacity and low charge platform of Co 1− x Se 2 /GE could achieve high energy and power densities in full‐cell applications [22] …”

In Situ Growth of CoSe2 Coated in Porous Carbon Layers as Anode for Efficient Sodium‐Ion Batteries

“…In the subsequent cycles, the reduction peak at 1.46, 1.15, and 0.69 V and the oxidation peak at 1.83 V are considered as the Na þ ion insertion and extraction reactions, respectively. [29,30] After the initial cycle, the cathode peak intensity is significantly reduced, indicating a large irreversible capability loss, which caused by the formation of SEI layer. The second and third cycle curves are nearly overlapped, indicating the excellent reversibility of the electrode materials.…”