Phase Engineering of Nickel Sulfides to Boost Sodium‐ and Potassium‐Ion Storage Performance

Abstract

Sulfides are promising anode candidates because of their relatively large theoretical discharge/charge specific capacity and pretty small volume changes, but suffers from sluggish kinetics and structural instability upon cycling. Phase engineering can be designed to overcome the weakness of the electrochemical performance of sulfide anodes. By choosing nickel sulfides (α‐NiS, β‐NiS, and NiS2) supported by reduced graphene oxide (rGO) as model systems, it is demonstrated that the nickel sulfides with different crystal structures show different performances in both sodium‐ion and potassium‐ion batteries. In particular, the α‐NiS/rGO display superior stable capacity (≈426 mAh g−1 for 500 cycles at 500 mA g−1) and exceptional rate capability (315 mAh g−1 at 2000 mA g−1). The combined density functional theory calculations and experimental studies reveal that the hexagonal structure is more conducive to ion absorption and conduction, a higher pseudocapacitive contribution, and higher mechanical ability to relieve the stress caused by the volume changes. Correspondingly, the phase engineered nickel sulfide coupled with the conducting rGO network synergistically boosts the electrochemical performance of batteries. This work sheds light on the use of phase engineering as an essential strategy for exploring materials with satisfactory electrochemical performance for sodium‐ion and potassium‐ion batteries.

An Open‐Ended Ni3S2–Co9S8 Heterostructures Nanocage Anode with Enhanced Reaction Kinetics for Superior Potassium‐Ion Batteries

“…Besides, the Ni-Co-S@rGO cages anode exhibited excellent competitiveness compared to the reported NiS x -based anodes and the CoS x -based anodes for PIBs, as shown in Figure S29 (Supporting Information) and Figure 5e. [23,24,28,29,37,[55][56][57][58][59] The excellent electrochemical performance of the Ni-Co-S@rGO cages Adv. Mater.…”

“…[23][24][25][26][27] For instance, Wu et al designed the anode of α-NiS coated with the reduced graphene oxide (α-NiS/rGO), which achieved high reversible capacity of 426 mAh g -1 after 500 cycles at 0.5 A g -1 . [28] Yu's group proposed a hierarchical porous conductive network loaded with CoS nanobox (CoS NP@NHC@MXene), demonstrating good potassium-storage capacity (210 mAh g -1 after 500 cycles at 2 A g -1 ). [29] However, the long-term lifespan and rate performances of these reported sulfides anodes are still unsatisfactorily to meet the practical application requirements owing to their intrinsic poor electronic conductivity, slow ion transport, and structural instability derived from the agglomeration or fragmentation during the conversion reaction process.…”

Harnessing Plasma‐Assisted Doping Engineering to Stabilize Metallic Phase MoSe2for Fast and Durable Sodium‐Ion Storage

“…Different from other kinds of sodium storage anode materials, the unique feature of polymorphism makes thermodynamically stable 2H-MoSe 2 capable of transforming to metallic phase (1T-MoSe 2 , octahedral Oh) to acquire manipulated crystal structure and electronic properties. [11][12][13][14][15] Unlike semiconducting 2H-MoSe 2 , 1T-MoSe 2 exhibits metallic property with Metallic-phase selenide molybdenum (1T-MoSe 2 ) has become a rising star for sodium storage in comparison with its semiconductor phase (2H-MoSe 2 ) owing to the intrinsic metallic electronic conductivity and unimpeded Na + diffusion structure. However, the thermodynamically unstable nature of 1T phase renders it an unprecedented challenge to realize its phase control and stabilization.…”

Prospects of Electrode Materials and Electrolytes for Practical Potassium‐Based Batteries

“…Other anode materials including metal chalcogenides [ 274–304 ] and Mxene‐based composite materials [ 302,305–320 ] have also been extensively investigated in recent years. Generally, the potassium storage mechanism in metal chalcogenides is a conversion reaction.…”