Jue Wang

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%.

Semimetallic vanadium molybdenum sulfide for high-performance battery electrodes

The ultrathin thickness and lateral morphology of a two dimensional (2D) MoS2 nanosheet contribute to its high surface-to-volume ratio and short diffusion path, rendering it a brilliant electrode material for lithium-ion batteries (LIBs). However, the low conductivity and easy restacking character of the pure MoS2 nanosheet during extended cycling result in severe capacity fading and poor cycling performance. In this work, we developed an attractive strategy by using a metal-doping method to engineer chemical, physical and electronic properties of MoS2, achieving an outstanding performance in LIBs. The computational results show that V–Mo–S has semimetallic properties. Semimetallic vanadium molybdenum sulfide nanoarrays (V–Mo–S NAs) were prepared to overcome the low conductivity of semiconducting MoS2 and thus further optimize its performance in LIBs. A reversible capacity as high as 1047 mA h g−1 was achieved at 1000 mA g−1. It also displayed an excellent stability even after 700 cycles. This fascinating study may pave a way for utilizing semimetallic material-based nanomaterials for batteries.

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 55u202f000 cycles, this cathode retains a superior reversible specific capacity of 101.24 mAh g-1 at an ultrafast rate of 50u202f000 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 10u202f000 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.

An Ultrafast and Highly Stable Potassium-Organic Battery

Potassium-organic batteries have a great potential for applications in the grid-scale energy storage owing to their low cost and abundant resources, although they suffer from the inferior cycle stability, fast capacity decay, and low power density. A highly reversible phase transformation of the organic cathode during potassiation/depotassiation is the key factor for the capacity retention, as revealed here. Consequently, the potassium-organic battery achieves a high power density of 9796 W kg-1 , a remarkable energy efficiency of 89%, a long cycle stability for 1000 cycles, a superior areal capacity around 2 mA h cm-2 , and a long-term cycling time over 8 months. Besides, the full cells also exhibit a superior rate performance and good cycle stability over 3000 cycles. This work provides new insight into the stabilization of the organic cathode, and demonstrates the enormous potential of organic cathodes for application in high-power potassium-ion batteries (PIBs), which may bring PIBs to new heights.