Natural Polysaccharide Strengthened Hydrogel Electrolyte and Biopolymer Derived Carbon for Durable Aqueous Zinc Ion Storage

Abstract

Aqueous zinc-ion hybrid supercapacitors (ZHSCs) represent one of the current research subjects because of their flame retardancy, ease of manufacturing, and exceptional roundtrip efficiency. With the evolution into real useful energy storage cells, the bottleneck factors of the corrosion and dendrite growth problems must be properly resolved for largely boosting their cycling life and energy efficiency. Herein, a natural polysaccharide strengthened hydrogel electrolyte (denoted as PAAm/agar/Zn­(CF3SO3)2) was engineered by designing an asymmetric dual network of covalently cross-linked polyacrylamide (denoted as PAAm) and physically cross-linked loose polysaccharide (e.g., agar) followed by intense uptake of Zn­(CF3SO3)2 aqueous electrolyte. In this polymeric matrix, the PAAm chains are responsible for constructing the soft domains to immobilize the water molecules, and the agar component boosts the mechanical performance (by using its inherent reversible sacrificial bonds) and favors the electrolyte ion transport. Due to these reasons, the as-designed hydrogel electrolyte effectively inhibits the zinc dendrite growth, realizes the uniform Zn deposition, and affords a satisfactory ionic conductivity of 1.55 S m–1, excellent tensile strength (78.9 kPa at 507.7% stretchable), and high compression strength (118.0 kPa at 60.0% strain). Additionally, a biopolymer-derived N-doped carbon microsphere cathode material with a highly interconnected porous carbonaceous network (denoted as NC) was also synthesized, which delivers a high capacity of 92.8 mAh g–1, along with superb rate capability and long duration cycling lifespan (95.4% retention for 10000 cycles) in the aqueous Zn//NC ZHSC. More notably, with integrated merits of the PAAm/agar/Zn­(CF3SO3)2 hydrogel electrolyte and NC, the as-built quasi-solid-state ZHSC achieves a high specific capacity of 73.4 mAh g–1 and superior energy density of 61.3 Wh kg–1 together with excellent cycling stability for 10000 cycles. This work demonstrated favorable practicability in the structural design of the hydrogel electrolytes and electrode materials for advanced ZHSC applications.

Construction of zwitterionic osmolyte-based hydrogel electrolytes towards stable zinc anode for durable aqueous zinc ion storage and integrated electronics

“…Additionally, new signals located at 1241, 1161, 1030, and 637 cm −1 can be detected, which correspond to the symmetric CF 3 stretching vibration, asymmetric CF 3 stretching vibration, symmetric SO 3 stretching vibration, and asymmetric SO 3 bending of CF 3 SO 3 − anion, respectively. 34–36 The obtained results suggested that the SPS–Zn hydrogel electrolyte was successfully synthesized.…”

All-round supramolecular zwitterionic hydrogel electrolytes enabling environmentally adaptive dendrite-free aqueous zinc ion capacitors

“…S65, S66, Table S4, ESI †). 66,[83][84][85][86][87][88] To further examine the real-time influence of environment on the output performance of the CP/EGZn/betaine ZICs in practical application, they were tested in a thermostat with the temperature varying from À40 1C to 80 1C. Intriguingly, the quasi-solid ZICs could endure both low and high temperature tests in turn, and their capacity well recovered when the temperature was set back to 20 1C (Fig.…”

“…CP/EGZn/betaine-based ZIC: (c) cycling stability at 2 A g À1 ; (d) capacity and Coulombic efficiency plots at 0.5 A g À1 at different temperatures from À40 1C to 20 1C and from 20 1C to 80 1C. (f) Ragone plot of ZICs in comparison with previously reported ZICs based on different hydrogel electrolytes 66,[83][84][85][86][87][88]. Continuous destructive tests include (e) hammering test, (g) squeezing, rolling, folding, and compressing, and (h) punching and cutting.…”

A flexible and stable zinc-ion hybrid capacitor with polysaccharide-reinforced cross-linked hydrogel electrolyte and binder-free carbon cathode

“…6e, the energy density of the as-made quasi-solid-state ZHC reaches 113.2 W h kg −1 at a power density of 206.2 W kg −1 , and its power density can be 15 752.4 W kg −1 at 43.8 W h kg −1 , displaying high energy and power outcomes for this flexible device. Moreover, the energy density achieved for our device outstrips that of many other energy-storage systems, such as WC-6ZnN-12U//Zn@CC (27.7 W h kg −1 at 35.7 W kg −1 ), 49 HIWW-based EDLCs (39.1 W h kg −1 at 391 W kg −1 ), 64 P–Co 3 O 4 @P, N–C//Co@P, N–C (47.6 W h kg −1 at 750 W kg −1 ), 65 NPFC 700 -based ZHC (60.1 W h kg −1 at 74.2 W kg −1 ), 66 Zn//PAAm/agar/Zn(CF 3 SO 3 ) 2 //NC (61.3 W h kg −1 at 209.0 W kg −1 ), 67 MoO 2 @NC//CuCo 2 S 4 (65.1 W h kg −1 at 800 W kg −1 ), 68 CNPK-based quasi-solid-state ZHC (89.3 W h kg −1 at 79.0 W kg −1 ), 69 and quasi-solid-state BCF-based ZSC (100.8 W h kg −1 at 400.8 W kg −1 ), 70 (Fig. 6e).…”