Dual Play of Chitin‐Derived N‐Doped Carbon Nanosheets Enabling High‐Performance Na‐SeS₂ Half/Full Cells

Abstract

Room-temperature NaÀ S batteries hold great promise for developing next-generation battery system with the advantages of abundant resource, high energy density, and long lifetime. However, limited by sluggish kinetics, NaÀ S batteries frequently suffer from low utilization of active materials, rapid capacity decay during cycling and poor rate capability. Herein, we propose an advanced cathode with SeS 2 tightly impregnated in chitin-derived rich nitrogen carbon nanosheets (termed as CCN/ SeS 2 ). The CCN/SeS 2 exhibits superb rate capability (422 mAh g À 1 at 5 A g À 1 ) and long cycle stability (566 mAh g À 1 after 470 cycles with a capacity decay rate of 0.056 % per cycle).High content and high loading cathodes are also fabricated to meet the requirement of practical application. The results of electrochemical tests and characterization demonstrate that CCN/SeS 2 has preponderance in lowering overpotential and reaction resistances, prompting the diffusion of sodium ions and achieving the uniform deposition of discharge products. For the first time, a full cell based on all-chitin materials (CCN/ SeS 2 cathode and CCN anode) is assembled, which exhibits favorable cycling performance over 100 cycles. The as-obtained cell using a green and low-cost carbon and SeS 2 inheriting the advantages of Se and S may pave a new way to energy storage.[a] J.

A Strategy for Polysulfides/Polyselenides Protection Based on Co9S8@SiO2/C Host in Na‐SeS2 Batteries

“…The first cathodic scan exhibits three characteristic peaks at about 1.5, 0.9, and 0.5 V, respectively. The peak at 1.5 V is ascribed to the reduction of SeS 2 , [ 25 ] while the broad peak at 0.9 V corresponds to the multi‐step reduction of Co 9 S 8 into metallic Co and Na 2 S. [ 26 ] The last peak at 0.5 V may be derived from the formation of solid electrolyte interface (SEI) layers. In the subsequent anodic scan, the CV curve displays four characteristic peaks at 0.8, 1.7, 1.9, and 2.35 V, respectively.…”

Rechargeable Potassium–Selenium Batteries

“…On the one hand, Se x S y alloys may help maintain the high capacity of S and also improve the poor electronic conductivity of S by virtue of the presence of Se. [71][72][73] The capacities of Se x S y cathodes are far higher than that of S and slightly lower than Se, and the proportion of Se and S in Se x S y alloys can be flexibly tuned. On the other hand, it should be noted that Se x S y cathodes exhibit very similar electrochemical properties with Se, so they may also face some tendency toward shuttle effect and large volume changes during cycling.…”

Recent Advances of Catalytic Effects in Cathode Materials for Room‐Temperature Sodium‐Sulfur Batteries

“…[12] In addition, the covalent bonds between S and polymers or metal sulfides/oxides with chemical adsorptions in cathodes have been reported to prevent polysulfide dissolution for enhanced RT-Na/S properties. The latest related research mainly focused on chemisorption of S-polyacrylonitrile (PAN) bonds, [13] S-metal sulfides (MoS 5.6 , [14] SeS 2 , [15] CoNi 2 S 4 [16] ), and S-metal oxides (MnO 2 ). [17] However, the utilization of physical confinement and chemical adsorption in S-based cathodes cannot accurately control the complex process of polysulfide conversion.…”