A new energy storage system: Rechargeable potassium-selenium battery

Abstract

A new reversible and high-performance potassium-selenium (K-Se) battery, using confined selenium/ carbonized-polyacrylonitrile (PAN) composite (c-PAN-Se) as cathode and metallic potassium as anode, is reported in this work. The PAN-derived carbon matrix could effectively confine the small Se molecules and provide a sufficient buffer for the volume changes. The reversible formation of small-molecule trigonal Se (Se1, P3121) phase could essentially inhibit the formation of polyselenides and account for outstanding electrochemical performance. The carbonate-based electrolyte further synergistically diminishes the shuttle effect by inhibiting the formation of polyselenides in the meantime. The as-prepared K-Se battery shows a reversible capacity of 1904 mAh cm¿3after 100 cycles at 0.2 C and rate retention of 89% from 0.1 to 2 C. In addition, the charge-discharge mechanism is also investigated via the combination of in-situ and ex-situ synchrotron X-ray diffraction (XRD), and Raman spectroscopy analysis. The results reveal that the introduction of K+ions leads to the cleavage of C-Se bonds, the rearrangement of selenium atoms, and the final formation of the main product K2Se. Moreover, the reversible formation of trigonal Se (Se1, P3121) phase was detected in the reaction with K+. These findings not only can advance our understanding of this family of batteries, but also provide insight into chemically-bonded selenium composite electrodes, which

Sodium/Potassium‐Ion Batteries: Boosting the Rate Capability and Cycle Life by Combining Morphology, Defect and Structure Engineering

“…As for the cycling stability, the N‐CNS performs the best reversible capacity and capacity retention among all anodes investigated here (Figure c), confirming the importance of pyridinic‐N/pyrrolic‐N‐doping in carbon as anode for PIBs . The rate capability of our N‐CNS anode also exceeds all other carbon‐based anode materials for PIBs (Figure d) . Compared with other carbon‐based electrodes reported for PIBs in the literature (Table S2, Supporting Information), the N‐CNS delivers unprecedented long cycle performance (321 mAh g −1 at 5 A g −1 after 5000 cycles), superior rate performance (145 mAh g −1 at 20 A g −1 after 5000 cycles), and high Coulombic efficiency (≈100%) (Figure e and Figure S11, Supporting Information) .…”

A Dual‐Carbon Battery Based on Potassium‐Ion Electrolyte

“…Consequently, novel battery systems such as sodium-ion batteries (SIBs), [3] aluminum-ion batteries (AIBs), [4] and dual-ion batteries (DIBs) [5][6][7][8][9][10][11] characterized by higher abundance and lower cost have attracted extensive attentions. [12][13][14][15][16][17] Compared anode based on the KPF 6 containing organic electrolyte. [12][13][14][15][16][17] Compared anode based on the KPF 6 containing organic electrolyte.…”

“…Apparently, the dual-graphite DIBs show advantages in terms of low cost, good safety, and environmental friendliness. [12][13][14][15][16][17] Compared 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.…”

Long Cycle Life, Low Self‐Discharge Sodium–Selenium Batteries with High Selenium Loading and Suppressed Polyselenide Shuttling

“…[25][26][27][28][29][30] However, the practical applications of RT NaS batteries are facing two major challenges: (i) sulfur has a low electronic conductivity (5 × 10 −30 S cm −1 at 25 °C), thus leading to sluggish electrochemical reaction processes and low utilization of the active sulfur in the electrode; (ii) severe "polysulfide shuttle effect," i.e., migration of dissolved polysulfide intermediate products through the porous separator between the cathode and the anode, which leads to rapid capacity fade during cycling. Selenium is a chemical analogue of S [32,33] and is considered to be an alternative electrode materials for SIBs due to its much higher electronic conductivity (1 × 10 −3 S m −1 ) as indicated in Figure S1 in the Supporting Information, volumetric capacity (3253 A h L −1 ) comparable to that of S (3467 A h L −1 ), and stable function in the relatively low-cost carbonate-based electrolytes. However, the intrinsic challenges of RT NaS batteries have been far from completely solved.…”