Suhua Chen

Potassium‐Based Dual Ion Battery with Dual‐Graphite Electrode

A potassium ion battery has potential applications for large scale electric energy storage systems due to the abundance and low cost of potassium resources. Dual graphite batteries, with graphite as both anode and cathode, eliminate the use of transition metal compounds and greatly lower the overall cost. Herein, combining the merits of the potassium ion battery and dual graphite battery, a potassium-based dual ion battery with dual-graphite electrode is developed. It delivers a reversible capacity of 62 mA h g-1 and medium discharge voltage of ≈3.96 V. The intercalation/deintercalation mechanism of K+ and PF6- into/from graphite is proposed and discussed in detail, with various characterizations to support.

Carbon Thin Film Wrapped around a Three-Dimensional Nitrogen-Doped Carbon Scaffold for Superior-Performance Supercapacitors

A carbon thin film/carbon foam core/sheath structure was synthesized by chemical vapor deposition (CVD) on carbonized melamine foam. It has a specific capacitance of 310 F g-1 at a current density of 1 A g-1 and shows outstanding electrochemical performance in both aqueous and water-in-salt electrolytes. Electrochemical analysis by cyclic voltammetry and galvanostatic charge/discharge testing revealed a large capacitive contribution up to more than 90 % of its total capacitance. The core/sheath structure has advantages in ion transport and a high degree of utilization of the electrode surface, and the synthetic process provides a way to coat carbon thin film on any substrate by nickel-catalyzed CVD.

Ultrastable Potassium Storage Performance Realized by Highly Effective Solid Electrolyte Interphase Layer

Potassium ion-batteries (PIBs) have attracted tremendous attention recently due to the abundance of potassium resources and the low standard electrode potential of potassium. Particularly, the solid-electrolyte interphase (SEI) in the anode of PIBs plays a vital role in battery security and battery cycling performance due to the highly reactive potassium. However, the SEI in the anode for PIBs with traditional electrolytes is mainly composed of organic compositions, which are highly reactive with air and water, resulting in inferior cycle performance and safety hazards. Herein, a highly stable and effective inorganic SEI layer in the anode is formed with optimized electrolyte. As expected, the PIBs exhibit an ultralong cycle performance over 14 000 cycles at 2000 mA g-1 and an ultrahigh average coulombic efficiency over 99.9%.

Offset Initial Sodium Loss To Improve Coulombic Efficiency and Stability of Sodium Dual-Ion Batteries

Sodium dual-ion batteries (NDIBs) are attracting extensive attention recently because of their low cost and abundant sodium resources. However, the low capacity of the carbonaceous anode would reduce the energy density, and the formation of the solid-electrolyte interphase (SEI) in the anode during the initial cycles will lead to large amount consumption of Na+ in the electrolyte, which results in low Coulombic efficiency and inferior stability of the NDIBs. To address these issues, a phosphorus-doped soft carbon (P-SC) anode combined with a presodiation process is developed to enhance the performance of the NDIBs. The phosphorus atom doping could enhance the electric conductivity and further improve the sodium storage property. On the other hand, an SEI could preform in the anode during the presodiation process; thus the anode has no need to consume large amounts of Na+ to form the SEI during the cycling of the NDIBs. Consequently, the NDIBs with P-SC anode after the presodiation process exhibit high Coulombic efficiency (over 90%) and long cycle stability (81 mA h g-1 at 1000 mA g-1 after 900 cycles with capacity retention of 81.8%), far more superior to the unsodiated NDIBs. This work may provide guidance for developing high performance NDIBs in the future.

Carbon Nanoscrolls for Aluminum Battery

This design provides a scalable route for in situ synthesizing of special carbon nanoscrolls as the cathode for an aluminum battery. The frizzy architectures are generated by a few graphene layers convoluting into the hollow carbon scroll, possessing rapid electronic transportation channels, superior anion storage capability, and outstanding ability of accommodating a large volume expansion during the cycling process. The electrochemical performance of the carbon nanoscroll cathode is fully tapped, displaying an excellent reversible discharge capacity of 104 mAh g-1 at 1000 mA g-1. After 55 000 cycles, this cathode retains a superior reversible specific capacity of 101.24 mAh g-1 at an ultrafast rate of 50 000 mA g-1, around 100% of the initial capacity, which demonstrates a superior electrochemical performance. In addition, anionic storage capability and structural stability are discussed in detail. The battery capacity under a wide temperature range from -80 to 120 °C is examined. At a low temperature of -25 °C, the battery delivers a discharge capacity of 62.83 mAh g-1 after 10 000 cycles, obtaining a capacity retention near 100%. In addition, it achieves a capacity of 99.5 mAh g-1 after 4000 cycles at a high temperature of 80 °C, with a capacity retention close to 100%. The carbon nanoscrolls possess an outstanding ultrafast charging/variable discharging rate performance surpassing all the batteries previously reported, which are highly promising for being applied in energy storage fields.

Simultaneous Suppression of the Dendrite Formation and Shuttle Effect in a Lithium-Sulfur Battery by Bilateral Solid Electrolyte Interface

Abstract Although the reversible and inexpensive energy storage characteristics of the lithium–sulfur (Li‐S) battery have made it a promising candidate for electrical energy storage, the dendrite growth (anode) and shuttle effect (cathode) hinder its practical application. Here, it is shown that new electrolytes for Li‐S batteries promote the simultaneous formation of bilateral solid electrolyte interfaces on the sulfur‐host cathode and lithium anode, thus effectively suppressing the shuttle effect and dendrite growth. These high‐capacity Li‐S batteries with new electrolytes exhibit a long‐term cycling stability, ultrafast‐charge/slow‐discharge rates, super‐low self‐discharge performance, and a capacity retention of 94.9% even after a 130 d long storage. Importantly, the long cycle stability of these industrial grade high‐capacity Li‐S pouch cells with new electrolytes will provide the basis for creating robust energy dense Li‐S batteries with an extensive life cycle.