Hollow MoS₂ Spheres Confined in Carbon Fibers for Ultralong-life Potassium Storage

Abstract

Potassium-ion energy storage systems are gradually showing their status due to abundant potassium resources and low cost. Unfortunately, K + storage materials are still an exigent issue due to the large radius and sluggish kinetics of K + . Herein, a composite electrode (H-MoS 2 @CNFs) built by electrospun carbon fibers (CNFs) as the frame and the hollow MoS 2 spherical shell as the inner core is designed. H-MoS 2 @CNFs is endowed with the following preponderance: the outside CNFs interlocked with the MoS 2 nanosheets play a triple role in conducting electrons, buffering the volume expansion of MoS 2 , and maintaining the structural stability of the electrode; the exposed edges of the (002) plane of MoS 2 nanosheets in direct contact with the electrolyte stored in the internal cavity facilitate the K + reaction kinetics. As the anode of potassiumion batteries, H-MoS 2 @CNFs delivers an excellent cyclic performance (187.7 mAh g −1 at 2.0 A g −1 after 5000 cycles with 0.0037% decay per cycle) and high rate capability (184.7 mAh g −1 at 10.0 A g −1 ). Furthermore, owing to the superior potassium storage and freestanding characteristics without the binder and conductive additives, the potassium-ion capacitor (PIC) based on the anode exhibits a high energy density of 165 Wh kg −1 at a power density of 378 W kg −1 , which furnishes a reliable basis for the development of two-dimensional materials for the PIC.

Synchronous embedded growth of Mo2C nanodisk arrays immobilized on porous carbon nanosheets for ultra-stable sodium storage

“…The surface capacitance contribution at different scan rates was further quantified by eqn (6): i = k 1 v + k 2 v ½ where k 1 and k 2 are constants and the current response ( i ) can be decomposed into k 1 v (capacitive control) and k 2 v ½ (diffusion control). 54 As shown in Fig. 4f, the Mo 2 C/C-2 electrode shows a high surface-controlled current response (84%) at 1.2 mV s −1 .…”

Comprehensive Insights into Potassium‐Ion Capacitors: Mechanisms, Materials, Devices and Future Perspectives

“…H-FeS 2 @3DCS//NSPC [142] 0-4.0 118 10 000 87% after 18 000 cycles; 2 A g −1 CoSe 2 @Ti 3 C 2 T n //AC [153] 0.01-3 199.0 ≈1160 84.8% after 6000 cycles; 0.2 A g −1 Co 2 P/MoSe 2 @NC//AC [286] 0-4.0 107.2 22 263.7 74.5% after 3000 cycles; 1 A g −1 MoS 2 @MCNWs-2 //AC [287] 0.5-4.0 106.5 9703.9 97.6% after 6000 cycles; 1 A g −1 H-MoS 2 @CNFs//ACFMs [ 288] 0.01-3.9 165 8348 81.8% after 10 000 cycles; 4 A g −1 MCO@MCS@rGO//AC [140] 1.0-4.0 85.3 9000 76.6% after 5000 cycles; 2 A g −1 MCT-NC@rGO//PAC [154] 0-4.0 111.3 8413.3 95% after 6000 cycles; 1 A g −1 FeS 2 /rGO-NPC//AC [289] 0.5-4.0 134 17 973 91% after 15 000 cycles; 2 A g −1 c-SnNC-HNA 0.75/800 //AC [ 215] 0.1-3.5 112.5 7369.0 97.6% after 10 000 cycles; 0.5 A g −1 MoSe 2 ⊂CNB//AC [ 290] 0.01-4.0 130.7 13 607 97.6% after 10 000 cycles; 0.5 A g −1 WS 2 @NCNs//NCHS [ 141] 0.5-4.2 103.4 4700 78% after 500 cycles; 0.5 A g −1 N-MoSe 2 /G//AC [24] 0.5-4.0 119 7212 75.2% after 3000 cycles; 1 A g −1 MoSe 2 -AC [ 291] 1.0-4.0 169 588 81.58% after 1000 cycles; 1 A g −1 ED-MoS 2 @CT//PC [143] 0-4.0 148 21 000 70.2% after 10 000 cycles; 5 A g −1 rGO-NiMoO 4 @Ni-Co-S//rGO-MDC [ 118] 0-1.8 801.8 7980 90.89% after 10 000 cycles; 5 A g −1 Mo 2 C/NCNFs//AC [ 126] 0.01-3.8 88.2 629.9 80.4% after 1000 cycles; 0.5 A g −1 NCOP//BCN [70] 0.01-4.5 166.5 22 500 86.5% after 10 000 cycles; 5 A g −1 𝛼-NiS-NSCN//CHCF [ 137] 0-4 187 8400 85.6% after 3500 cycles; 2 A g −1 AC//PB [83] 0-1.9 28 1890 98% after 1200 cycles; 2 A g −1 CAC//KMCO [ 84] 0-3.0 43 30 000 88% after 30 000 cycles; 10 A g −1 K 2 TP//PANI [ 81] 1.0-4.0 153 6795 80% after 10 000 cycles; 2 A g −1 MoS 2 //KMF-2 [ 292] 0-1.8 62 -91.3% after 10 000 cycles; 1 A g −1 AC//PB [293] 0-3 48 1247 87% after 2000 cycles; 0.25 A g −1 BPNS//AC [87] 0-4.3 93 9380 99.5% after 6500 cycles; 1 A g −1 HA//AC [ 88] 0.01-3. PICs configurations combining battery-type anodes with pseudocapacitive cathodes.…”

Carbon-based flexible electrodes for electrochemical potassium storage

“…Spheres/CNFs [100] 1.0 M KFSI EC/DMC (1:1) 0.01-3.0 V 366.1 mA h g −1 @0.1 A g −1 /100 cycles 187.7 mA h g −1 @2.0 A g −1 /5000 cycles 184.7 mA h g −1 @10.0 A g −1 Activated carbon fiber membrane/Coin cell 0.01-4.0 V 81.8% capacity retention@4.0 A g −1 /10000 cycles 51 W h kg −1 @8348 W kg −1 B, F co-doped CNFs [101] 1.0 M KFSI EC/DEC (1:1) 0-3.0 V 259 mA h g −1 @0.1 A g −1 /120 cycles 176 mA h g −1 @1.0 A g −1 /6000 cycles 150 mA h g −1 @5.0 A g −1 Activated carbon/Coin cell 0.01-4.0 V 78% capacity retention@1.0 A g −1 /4000 cycles 23 W h kg −1 @14710 W kg −1 α-NiS nanocrystallite/CN Ts [98] 1.0 M KPF6 EC/DEC (1:1)…”