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Developing carbon-based materials with high catalytic performance and sensitivity has significance in low-cost and highly efficient nanozymes. Herein, for the first time, Cu,N-codoped hollow carbon nanospheres (CuNHCNs) with highly active Cu-Nx sites were successfully assembled through a template-free strategy, in which Cu

A Li3PO4 nanocoating was successfully constructed via controlling the reaction between a nickel-rich cathode material and a preformed phosphorus-containing polymeric nanoshell, which contributes to much-improved electrochemical performance.

To develop high-efficient near-infrared (NIR) gold (Au)-based photothermal nanomaterials, the architectures of two-dimensional nanoplate/nanosheet or nanoparticles with hollow interiors could be two favorable options to realize the red-shift of the...

The development of PIBs is challenged by the availability of suitable cathode materials capable of stably hosting the large-sized K+, whose continuous intercalation/deintercalation in the crystalline framework will cause serious phase deformation and irreversible structure degradation. Here, we demonstrated the possibility of achieving a highly reversible potassiation/depotassiation process in a layered metal oxide of K5/9Mn7/9Ti2/9O2. We confirmed that the existence of Ti can effectively combat the transition metal slab gliding of the P2-type structure during the electrochemical reaction. The destructive P2–O2 phase transition was efficiently diminished even when charged to a high voltage of 4.2 ​V, instead forming a stable OP4 phase which was able to switch back to its pristine P2-type structure upon discharge, accordingly providing an improved electrochemical performance of PIBs. We expect that the discovery and fundamental understanding of such a reversible P2-OP4 phase transition provide insights in the structural design of PIBs cathodes.

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Sodium-ion batteries (SIBs) are promising candidates for large-scale electric energy storage with abundant sodium resources. However, their development is challenged by the availability of satisfac...

K-ion batteries (KIBs) are drawing increasing research interest as a promising supplement of Li-ion batteries due to the natural abundance of K resource. However, due to the large size of K+, high-capacity anodes are challenged by the structural stability of the active materials which are susceptible to large volumetric deformation after incorporating with a sufficient number of K+. Herein, using SnS2/graphene as an example, we demonstrated that high-performance KIBs anode could be achieved through collaborative efforts targeting on both the active material and the prepared electrode film. The electrochemically-active species of SnS2 were controlled into small nanoparticles with their size below 5 nm to provide sufficient reactive sites for K+ storage. Meanwhile, highly-resilient electrode film based on the prepared SnS2/graphene nanocomposite was built on aluminum (Al) current collector rather than the widely-used copper foil, forming a strong anode film with high peel strength to endure the potassiation/depotassiation process. In this way, the active species was able to deliver an extraordinary reversible capacity of 610 mAh g−1 with unprecedented high-rate capability (around 290 mAh g−1 at 2A g−1) and promising cycling stability. This contribution sheds light on the rational design of high-performance electrode for KIBs and beyond.

Due to the obvious advantage in potassium reserves, potassium-ion batteries (PIBs) are now receiving increasing research attention as an alternative energy storage system for lithium-ion batteries (LIBs). Unfortunately, the large size of K+ makes it a challenging task to identify suitable electrode materials, particularly cathode ones that determine the energy density of PIBs, capable of tolerating the serious structural deformation during the continuous intercalation/deintercalation of K+ . It is therefore of paramount importance that proper design principles of cathode materials be followed to ensure stable electrochemical performance if a practical application of PIBs is expected. Herein, the current knowledge on the structural engineering of cathode materials acquired during the battle against its performance degradation is summarized. The K+ storage behavior of different types of cathodes is discussed in detail and the structure-performance relationship of materials sensitive to their different lattice frameworks is highlighted. The key issues facing the future development of different categories of cathode materials are also highlighted and perspectives for potential approaches and strategies to promote the further development of PIBs are provided.

The development of high energy electrode materials for lithium ion batteries is challenged by their inherent instabilities, which become more aggravated as the energy densities continue to climb, accordingly causing increasing concerns on battery safety and reliability. Here, taking the high voltage cathode of LiNi0.5Mn1.5O4 as an example, we demonstrate a protocol to stabilize this cathode through a systematic phase modulating on its particle surface. We are able to transfer the spinel surface into a 30 nm shell composed of two functional phases including a rock-salt one and a layered one. The former is electrochemically inert for surface stabilization while the latter is designated to provide necessary electrochemical activity. The precise synthesis control enables us to tune the ratio of these two phases, and achieve an optimized balance between improved stability against structural degradation without sacrificing its capacity. This study highlights the critical importance of well-tailored surface phase property for the cathode stabilization of high energy lithium ion batteries.

Due to their abundant resources and potential price advantage, potassium-ion batteries (KIBs) have recently drawn increasing attention as a promising alternative to lithium-ion batteries (LIBs) for their applications in electrochemical energy storage applications. Despite the continuous progress in identifying possible electrode materials, the development of KIBs has been challenged by different problems including low reversible capacities, unsatisfactory cycling stability, and insufficient energy density, which become serious concerns for the practical application of KIBs. In this review, we will summarize the recent advancements in both cathode and anode materials with focus on their structure–performance relationship. Meanwhile, challenges and opportunities related to the future development of KIBs are also discussed.

Titanium niobium oxides emerge as promising anode materials with potential for applications in lithium ion batteries with high safety and high energy density. However, the innate low electronic conductivity of such a composite oxide seriously limits its practical capacity, which becomes a serious concern especially when a high rate charge/discharge capability is expected. Here, using a modified template-assisted synthesis protocol, which features an in-situ entrapment of both titanium and niobium species during the formation of polymeric microsphere followed by a pyrolysis process, we succeed in preparing hollow microspheres of titanium niobium oxide with high efficiency in structural control. When used as an anode material, the structurally-controlled hollow sample delivers high reversible capacity (103.7 mA h g−1 at 50 C) and extraordinary cycling capability especially at high charge/discharge currents (164.7 mA h g−1 after 500 cycles at 10 C).

The construction of uniform core–shell nanostructures using transition-metal phosphates as the shell has been a long-standing challenge in the field of nanotechnology. Due to their extremely low solubility constants, metal phosphates are prone to precipitate independently in solution, making a heterogeneous growth around the preexisting seeds extremely hard to achieve. Here, we demonstrated that it is possible to overcome the hurdles arising from their intrinsic growth habit, and form uniform metal phosphate nanoshells with their thickness tuned with nanometer accuracy. Particularly, for the formation of different nanoshells including Ni3(PO4)2, Co3(PO4)2, and Mn3(PO4)2, it has been found that a cooperative effort to control both the solvent environment and the precipitating agent is critical to tuning the growth kinetics of these metal phosphates, making it convenient for us to grow uniform nanoshells around a large variety of seeds. The application of this synthetic protocol for the surface treatment of LiNi0.5Mn1.5O4, a well-known high voltage cathode material in lithium ion batteries, demonstrates that a 4 nm coating layer of Co3(PO4)2 can be achieved as a protective shell, which provides a much improved cycling stability to the electrode and holds promising potential for its application as a high energy cathode.

A surface doping strategy is demonstrated for the stabilization of LiMn2O4, which is achieved by the surface solid reaction between the LiMn2O4 particle and its ZnO nanoshell. The surface treated sample shows a much improved high temperature performance with evidently suppressed Mn dissolution.

We identified that the growth kinetics of ZrO2 could be well-tuned in a CH3COOH-CH3COONa based buffer solution, which provided an efficient way to build uniform ZrO2 nanoshells on various substrates. Using this synthetic strategy, yolk-shell structured Pd@ZrO2 is demonstrated as a promising catalyst for methane oxidation.

Sodium-ion batteries (SIBs) are promising candidates for large-scale electric energy storage with abundant sodium resources. However, their development is challenged by the availability of satisfactory cathode materials with stable framework to accommodate the transportation of large-sized Na

Hollow carbon nanospheres (HCNs) have found broad applications in a large variety of application fields. Unfortunately, HCNs are known for their tedious operations and are incompetent for scalable synthesis for those widely adopted nanocasting-based routes. Here, we report a facile and highly efficient method for the creation of hollow carbon structures by tuning the growth kinetics of its polymeric precursor. We identified that a controlled polymerization of Cu

We report a simple and facile synthetic protocol to prepare an SnO2–C hollow composite, which shows improved battery performance when used as an anode material in lithium ion batteries.

We identified that the growth kinetics of ZrO2 could be well-tuned in a CH3COOH-CH3COONa based buffer solution, which provided an efficient way to build uniform ZrO2 nanoshells on various substrates. Using this synthetic strategy, yolk-shell structured Pd@ZrO2 is demonstrated as a promising catalyst for methane oxidation.

A surface doping strategy is demonstrated for the stabilization of LiMn2O4, which is achieved by the surface solid reaction between the LiMn2O4 particle and its ZnO nanoshell. The surface treated sample shows a much improved high temperature performance with evidently suppressed Mn dissolution.

We report a simple and facile synthetic protocol to prepare an SnO