Potassium-ion batteries (PIBs) are attracting intensive interest for large-scale applications due to the high natural abundance of potassium sources. However, the large radius of K+ makes it difficult for electrode materials to accommodate the repeated K+ insertion and extraction. Thus, developing high-performance electrode materials for PIBs remains a great challenge. Herein, we present the rational design and fabrication of hierarchical carbon-coated MoSe2/MXene hybrid nanosheets (MoSe2/MXene@C) as a superior anode material for PIBs. Specifically, the highly conductive MXene substrate can effectively relieve the aggregation of MoSe2 nanosheets and improve the electronic conductivity. Moreover, the carbon layer enables us to reinforce the composite structure and further enhance the overall conductivity of the hybrid nanosheets. Meanwhile, strong chemical interactions are found at the interface of MoSe2 nanosheets and MXene flakes, contributing to promoting the charge-transfer kinetics and improving the structural durability. Consequently, as an anode material for PIBs, the resulting MoSe2/MXene@C achieves a high reversible capacity of 355 mA h g–1 at 200 mA g–1 after 100 cycles and an outstanding rate performance with 183 mA h g–1 at 10.0 A g–1. The presented design strategy holds great promise for developing more-efficient electrode materials for PIBs.

Freestanding and highly compressible nitrogen-doped carbon foam (NCF) with excellent hydrophilicity and good electrochemical properties is prepared. Based on NCF electrodes, a high-performance all solid-state symmetric supercapacitor device is fabricated with native, full compressibility, and excellent mechanical stability, addressing two major problems in the current technology.

α-K0.19MnO2 nanotubes with high K+ content as cathodes for zinc-ion batteries show high capacity, excellent rate capability and cycling stability.

A freestanding SnO2@N-CNF film prepared by electrospinning exhibits excellent flexibility and a high surface area of 506 m(2) g(-1). When used as an anode for lithium-ion batteries, a high reversible capacity of 754 mAh g(-1) is maintained after the 300(th) cycle at 1 A g(-1) . Even when the current density increases to 5 A g(-1), the SnO2@N-CNF still delivers 245.9 mAh g(-1).

Supercapacitors and Li-ion batteries are two types of electrical energy storage devices. To satisfy the increasing demand for high-performance energy storage devices, traditional electrode materials, such as transition metal oxides, conducting polymers and carbon-based materials, have been widely explored. However, the results obtained to date remain unsatisfactory, and the development of inexpensive electrode materials (especially for commercial manufacturing) with superior electrochemical performance for use in supercapacitors and in Li-ion batteries is still needed. The as-prepared NiMoO 4 nanosheets (NSs) with interconnecting nanoscale pore channels and an ultrathin structure provide a large electrochemical active area, which facilitates electrolyte immersion and ion transport and provides effective pathways for electron transport. Therefore, the as-prepared NiMoO 4 NS electrode exhibits a high specific capacity and an excellent rate capability and cycling stability in supercapacitors and in Liion batteries. Moreover, a high energy density (43.5 W h kg -1 at 500 W kg -1 ) was obtained for the symmetric supercapacitor (SSC) composed of two sections of NiMoO 4 NSs.

Perovskites show excellent specific catalytic activity toward both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline solutions; however, small surface areas of the perovskites synthesized by traditional sol-gel methods lead to low utilization of catalytic sites, which gives rise to poor Li-O2 batteries performance and restricts their application. Herein, a hierarchical mesporous/macroporous perovskite La0.5Sr0.5CoO3-x (HPN-LSC) nanotube is developed to promote its application in Li-O2 batteries. The HPN-LSC nanotubes were synthesized via electrospinning technique followed by postannealing. The as-prepared HPN-LSC catalyst exhibits outstanding intrinsic ORR and OER catalytic activity. The HPN-LSC/KB electrode displays excellent performance toward both discharge and charge processes for Li-O2 batteries, which enhances the reversibility, the round-trip efficiency, and the capacity of resultant batteries. The synergy of high catalytic activity and hierarchical mesoporous/macroporous nanotubular structure results in the Li-O2 batteries with good rate capability and excellent cycle stability of sustaining 50 cycles at a current density of 0.1 mA cm(-2) with an upper-limit capacity of 500 mAh g(-1). The results will benefit for the future development of high-performance Li-O2 batteries using hierarchical mesoporous/macroporous nanostructured perovskite-type catalysts.

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Two-dimensional (2D) MnO2 ultrathin nanosheets have been assembled into three-dimensional (3D) aerogels, which can help prevent the restacking of 2D nanocrystals, and consequently lead to enhanced performances in Li–O2 batteries.