A Dual‐Carbon Battery Based on Potassium‐Ion Electrolyte

Abstract

with SIBs, potassium-ion batteries (KIBs) deliver a higher working voltage due to the lower redox potential of K + /K (−2.92 V vs SHE) than that of Na + /Na (−2.71 V vs SHE). [14] In addition, K + has been demonstrated to be reversibly intercalated/ deintercalated into graphite anode, while very limited amounts of Na + could. [14] However, as the research on KIBs is still at the infancy stage, the mechanisms at an atomic scale and interfaces are unclear. In addition, owing to the large size of K + that would cause sluggish kinetics, only a few of cathode materials (Prussian blue and its analogues) [16] and anode materials (graphite, [14] Sn 4 P 3 /C) [13] were investigated. Therefore, developing suitable electrode materials with good performance as well as comprehensively investigating the mechanism are of great importance.On the other hand, another new type of battery called dual-ion battery (DIB) [5][6][7][8][9][10][11] also arouses scientists' concern, which generally consists of dual graphitic carbon electrodes. Owing to the intrinsic redox amphotericity of graphitic carbon materials, both cations (Li + ) and anions (PF 6 − , BF 4 − , TFSI − , etc.) are intercalated/deintercalated into graphite anode and graphite cathode, respectively, during the charging/discharging process in the dual-graphite DIB. Apparently, the dual-graphite DIBs show advantages in terms of low cost, good safety, and environmental friendliness. In addition, the high working voltage (mainly above 4.5 V) [5] of the DIB caused by high anion intercalation potential is also beneficial for high energy density. Extensive researches on DIBs have been focused on exploiting high-capacity cathode materials, [6c] alternative anode materials, [6a,7-11] as well as suitable electrolyte compositions, [5] and great progresses on their development have been made.In this work, on the purpose of combining both advantages of KIBs and DIBs, we first report a dual-carbon battery (DCB) based on a potassium-ion electrolyte (1 m KPF 6 in carbonate solvent), using expanded graphite (EG) as cathode material and mesocarbon microbead (MCMB) as anode. The working mechanism of the as-prepared K-ion-based dual-carbon battery (named as K-DCB) was investigated, which was further demonstrated to deliver a reversible discharge capacity of 61 mA h g −1 at 1 C (1 C corresponding to 100 mA g −1 ) current rate and also show good cycling performance for 100 cycles with negligible capacity decay. Moreover, the battery works reversibly and stably over a wide voltage window of 3.0-5.2 V with medium discharge voltage of 4.5 V, the highest value among the reported KIBs. [12][13][14][15][16] Figure 1a schematically shows the working mechanism of the K-DCB configuration utilizing an EG cathode and MCMB Although potassium-ion batteries (KIBs) have been considered to be promising alternatives to conventional lithium-ion batteries due to large abundance and low cost of potassium resources, their development still stays at the infancy stage due to the lack of appropriate cathode and anod...

Electrolytes for Batteries with Earth‐Abundant Metal Anodes

“…In their experiments, they found that some commonly observed anions couldr eversibly intercalate into a graphite layer at high potential, such as AlCl 4 À ,F SI À ,P F 6 À , BF 4 À ,a nd C 6 H 5 CO 2 À (benzonate). [82][83][84][85][86][87] An alternative version of the dual-ion battery was also reported. However,t he dual-ion energy storagew ent almost uninvestigated for nearly ad ecade, duringw hich time only af ew studies focused on this promising aspect.…”

Strategies towards Low‐Cost Dual‐Ion Batteries with High Performance

“…The usage of the aluminum anode and graphite cathode significantly reduced the cost of DIBs. To further reduce the cost of DIBs, completely lithium‐free systems based on other low‐cost cations, such as Na + , K + , Ca 2+ , Al 3+ were also reported in recent years (Table ). Furthermore, in consideration of the future requirements of energy storage devices, such as high safety, flexibility, wearability, the new DIBs should be combined with all‐solid‐state batteries, organic batteries, and other aforementioned batteries.…”

Nanotube-like hard carbon as high-performance anode material for sodium ion hybrid capacitors

“…The development of ECs is restricted by low energy density [6][7][8]. On the contrary, the other type of crucial energy-storage devices such as electrochemical batteries including Li-ion [9,10], Li-O 2 [11,12], Li-S [13], Na-ion [14,15] and double-ion batteries [16,17], etc., have been extensively accepted to be durable and of high energy density to supply prolonged operation in a majority of electronic equipments. However, owing to slow insertion/extraction dynamics, these batteries show unsatisfactory power output.…”