Tin and its compounds hold promise for the development of high-capacity anode materials that could replace graphitic carbon used in current lithium-ion batteries. However, the introduced porosity in current electrode designs to buffer the volume changes of active materials during cycling does not afford high volumetric performance. Here, we show a strategy leveraging a sulfur sacrificial agent for controlled utility of void space in a tin oxide/graphene composite anode. In a typical synthesis using the capillary drying of graphene hydrogels, sulfur is employed with hard tin oxide nanoparticles inside the contraction hydrogels. The resultant graphene-caged tin oxide delivers an ultrahigh volumetric capacity of 2123 mAh cm–3 together with good cycling stability. Our results suggest not only a conversion-type composite anode that allows for good electrochemical characteristics, but also a general synthetic means to engineering the packing density of graphene nanosheets for high energy storage capabilities in small volumes.

We propose a novel material/electrode design formula and develop an engineered self-supporting electrode configuration, namely, silicon nanoparticle impregnated assemblies of templated carbon-bridged oriented graphene. We have demonstrated their use as binder-free lithium-ion battery anodes with exceptional lithium storage performances, simultaneously attaining high gravimetric capacity (1390 mAh g(-1) at 2 A g(-1) with respect to the total electrode weight), high volumetric capacity (1807 mAh cm(-3) that is more than three times that of graphite anodes), remarkable rate capability (900 mAh g(-1) at 8 A g(-1)), excellent cyclic stability (0.025% decay per cycle over 200 cycles), and competing areal capacity (as high as 4 and 6 mAh cm(-2) at 15 and 3 mA cm(-2), respectively). Such combined level of performance is attributed to the templated carbon bridged oriented graphene assemblies involved. This engineered graphene bulk assemblies not only create a robust bicontinuous network for rapid transport of both electrons and lithium ions throughout the electrode even at high material mass loading but also allow achieving a substantially high material tap density (1.3 g cm(-3)). Coupled with a simple and flexible fabrication protocol as well as practically scalable raw materials (e.g., silicon nanoparticles and graphene oxide), the material/electrode design developed would propagate new and viable battery material/electrode design principles and opportunities for energy storage systems with high-energy and high-power characteristics.

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A porous, yet compact, RuO /graphene hybrid is successfully prepared by using a disassembly-reassembly strategy, achieving effective and uniform loading of RuO nanoparticles inside compact graphene monolith. The disassembly process ensures the uniform loading of RuO nanoparticles into graphene monolith, while the reassembly process guarantees a high density yet simultaneously unimpeded ion transport channel in the composite. The resulting RuO /graphene hybrid possesses a density of 2.63 g cm , leading to a record high volumetric capacitance of 1485 F cm at the current density of 0.1 A g . When the current density is increased to 20 A g , it remains a high volumetric capacitance of 1188 F cm . More importantly, when the single electrode mass loading is increased to 12 mg cm , it still delivers a high volumetric capacitance of 1415 F cm at the current density of 0.1 A g , demonstrating the promise of this disassembly-reassembly approach to create high volumetric performance materials for energy storage applications.

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Clean and sustainable green energy, which is closely related to human lives, global economy and earth health, is one of the hottest topics in this century. In view of the inevitable exhaustion of fossil fuel resources and growing environmental worries that go with it, various new electrochemical energy storage/ conversion systems, such as lithium-ion batteries (LIBs), [1] electrochemical capacitors, [2] lithium-sulfur (Li-S) batteries, [3] and fuel cells (FCs) [4] emerged at the right moment. These new electrochemical energy storage/conversion systems have certain advantages in common that they are all characterized by wide applications, simplicity of operation, good mobility, little or no environmental pollution, and high energy and power Carbon-rich materials have drawn tremendous attention toward a wide spectrum of energy applications due to their superior electronic mobility, good mechanical strength, ultrahigh surface area, and more importantly, abundant diversity in structure and components. Herein, rationally designed and bottom-up constructed carbon-rich materials for energy storage and conversion are discussed. The fundamental design principles are itemized for the targeted preparation of carbon-rich materials and the latest remarkable advances are summarized in terms of emerging dimensions including sp 2 carbon fragment manipulation, pore structure modulation, topological defect engineering, heteroatom incorporation, and edge chemical regulation. In this respect, the corresponding structure-property relationships of the resultant carbon-rich materials are comprehensively discussed. Finally, critical perspectives on future challenges of carbon-rich materials are presented. The progress highlighted here will provide meaningful guidance on the precise design and targeted synthesis of carbon-rich materials, which are of critical importance for the achievement of performance characteristics highly desirable for urgent energy deployment.

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Promoting the efficient utilization of both the pores and heteroatoms remains a highly challenging endeavor, yet is of crucial significance to enhance the specific capacitance and energy density of carbon-based...