Sodium is globally available, which makes a sodium-ion rechargeable battery preferable to a lithium-ion battery for large-scale storage of electrical energy, provided a host cathode for Na can be found that provides the necessary capacity, voltage, and cycle life at the prescribed charge/discharge rate. Low-cost hexacyanometallates are promising cathodes because of their ease of synthesis and rigid open framework that enables fast Na(+) insertion and extraction. Here we report an intriguing effect of interstitial H2O on the structure and electrochemical properties of sodium manganese(II) hexacyanoferrates(II) with the nominal composition Na2MnFe(CN)6·zH2O (Na2-δMnHFC). The newly discovered dehydrated Na2-δMnHFC phase exhibits superior electrochemical performance compared to other reported Na-ion cathode materials; it delivers at 3.5 V a reversible capacity of 150 mAh g(-1) in a sodium half cell and 140 mAh g(-1) in a full cell with a hard-carbon anode. At a charge/discharge rate of 20 C, the half-cell capacity is 120 mAh g(-1), and at 0.7 C, the cell exhibits 75% capacity retention after 500 cycles.

Highly ordered mesoporous crystalline MoO(2) materials with bicontinuous Ia3d mesostructure were synthesized by using phosphomolybdic acid as a precursor and mesoporous silica KIT-6 as a hard template in a 10% H(2) atmosphere via nanocasting strategy. The prepared mesoporous MoO(2) material shows a typical metallic conductivity with a low resistivity ( approximately 0.01Omega cm at 300 K), which makes it different from all previously reported mesoporous metal oxides materials. Primary test found that mesoporous MoO(2) material exhibits a reversible electrochemical lithium storage capacity as high as 750 mA h g(-1) at C/20 after 30 cycles, rendering it as a promising anode material for lithium ion batteries.

A high performance TiNb 2 O 7 anode material with a nanoporous nature, which was prepared by a facile approach, exhibits an average storage voltage of 1.66 V, a reversible capacity of 281 mA h g À1 , and an 84% capacity retention after 1000 cycles, and may be suitable for long-life stationary lithium-ion batteries.

LiCoO2, discovered as a lithium‐ion intercalation material in 1980 by Prof. John B. Goodenough, is still the dominant cathode for lithium‐ion batteries (LIBs) in the portable electronics market due to its high compacted density, high energy density, excellent cycle life and reliability. In order to satisfy the increasing energy demand of portable electronics such as smartphones and laptops, the upper cutoff voltage of LiCoO2‐based batteries has been continuously raised for achieving higher energy density. However, several detrimental issues including surface degradation, damages induced by destructive phase transitions, and inhomogeneous reactions could emerge as charging to a high voltage (>4.2 V vs Li/Li+), which leads to the rapid decay of capacity, efficiency, and cycle life. In this review, the history and recent advances of LiCoO2 are introduced, and a significant section is dedicated to the fundamental failure mechanisms of LiCoO2 at high voltages (>4.2 V vs Li/Li+). Meanwhile, the modification strategies and the development of LiCoO2‐based LIBs in industry are also discussed.

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Ultrafine MoO 2 nanorods with a diameter of ∼5 nm were successfully synthesized by a nanocasting method using mesoporous silica SBA-15 as hard template. This material demonstrates high reversible capacity, excellent cycling performance, and good rate capacity as an anode electrode material for Li ion batteries. The significant enhancement in the electrochemical Li storage performance in ultrafine MoO 2 nanorods is attributed to the nanorod structure with small diameter and efficient one-dimensional electron transport pathways. Moreover, density functional theory calculations were performed to elucidate the Li uptake/ removal mechanism in the MoO 2 electrodes, which can help us understand the unique cycling behavior of MoO 2 material.

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We have established a facile and generalizable "silica-assisted" synthesis for diverse carbon spheres-a category that covers mesoporous carbon nanospheres, hollow mesoporous carbon nanospheres, and yolk-shell mesoporous carbon nanospheres-by using phenolic resols as a polymer precursor, silicate oligomers as an inorganic precursor, and hexadecyl trimethylammoniumchloride as a template. The particle sizes of the carbon nanospheres are uniform and easily controlled in a wide range of 180-850 nm by simply varying the ethanol concentrations. All three types of mesoporous carbon nanospheres have high surface areas and large pore volumes and exhibit promising properties for supercapacitors with high capacitance and favorable capacitance retention.