Carboxymethyl Cellulose Binder Greatly Stabilizes Porous Hollow Carbon Submicrospheres in Capacitive K-Ion Storage

Abstract

On account of the large radius of K-ions, the electrodes can suffer huge deformation during K-ion insertion and extraction processes. In our work, we unveil the impact of using carboxymethyl cellulose (CMC) instead of poly-(vinylidene fluoride) (PVDF) as binders for K-ion storage. Our porous hollow carbon submicrosphere anodes using the CMC binder exhibit a reversible capacity of 208 mA h g −1 after 50 cycles at 50 mA g −1 , and even at a high current density of 1 A g −1 , they achieve a reversible capacity of 111 mA h g −1 over 3000 cycles with almost no decay, demonstrating remarkably improved reversibility and cycling stability than those using PVDF (18 mA h g −1 after 3000 cycles at 1 A g −1 ). It is showed that the CMC binder can result in higher adhesion force and better mechanical performance than the PVDF binder, which can restrain the crack during a potassiation/depotassiation process. According to the test of adhesion force, the hollow carbon submicrospheres using the CMC binder show above three times of average adhesion force than that using the PVDF binder. Furthermore, based on the rational design, our hollow carbon submicrospheres also exhibit 62.3% specific capacity contribution below 0.5 V vs K/K + region, which is helpful to design the full cell with high energy density. We believe that our work will highlight the binder effect to improve the K-ion storage performance.

Rational Construction of Nitrogen‐Doped Hierarchical Dual‐Carbon for Advanced Potassium‐Ion Hybrid Capacitors

“…It is elucidated that three samples all exhibit a high degree of disorder, which is beneficial for K + storage. [ 29 ] The NMCP@rGO sample shows a higher I D / I G than that of rGO and NMCP, owing to the synergistic effect of the outer 2D rGO and inner NMCP. The outer carbon possesses abundant oxidative functional groups on the surface, while the inner NMCP acts as the scaffold to prevent the stack of 2D rGO.…”

“…This high rate and long cycling performance for the NMCP@rGO electrode are superior to previously reported works, as listed in Figure 3h and Table S2, Supporting Information. [ 2,14–16,20,38,22,28,29,34,36 ] The outstanding electrochemical performance of NMCP@rGO in PIBs is attributed to: i) the existence of robust chemical bonds and the multi‐dimensional inner@outer dual‐carbon structure that helps to form a robust crosslinked structure and offers fast transport pathways for both ions and electrons; ii) the abundant N‐doping and hierarchical pore structure makes full use of the capacitive effect, which leads to a high rate performance.…”

A Robust Solid Electrolyte Interphase Layer Augments the Ion Storage Capacity of Bimetallic‐Sulfide‐Containing Potassium‐Ion Batteries

“…[14,15] However,c arbonaceous materials exhibit ar elatively low reversible capacity because potassium-ion storage is limited by the insertion mechanism. [16,17] Therefore,further development of suitable anodes with high potassium-ion storage performance is an important issue.A mong the anode materials reported, transition-metal sulfides have drawn attention because of their appreciable electrochemical performance in KIBs. [18] Liu et al constructed thinly layered antimony sulfide/carbon sheet composites by solution-triggered one-step shear exfoliation, to produce an electrode with ah igh potassium-ion storage capacity (404 mAh g À1 at 500 mA g À1 after 200 cycles).…”

Self‐Supporting Electrode Composed of SnSe Nanosheets, Thermally Treated Protein, and Reduced Graphene Oxide with Enhanced Pseudocapacitance for Advanced Sodium‐Ion Batteries

“…Firstly, the 3D crosslinked structure composed of tin selenide nanosheets, thermally-treated BSA and reduced graphene oxide has been proven to have excellent structural stability and electron/ion conductivity, and in addition, has substantial interfacial sites for Na + redox reaction giving rise to additional pseudocapacitance, which is consistent with the previous report . [45][46] Moreover, the nitrogen has proven to originate from thermally treated BSA on the SnSe nanosheets surface. This result indicates that the selfsupporting SnSe-TP@rGO film electrode has better interface electrochemical properties because nitrogen doping has been shown to greatly enhance electron conductivity and charge transfer at the interface.…”