Advances in lithium ion batteries would facilitate technological developments inareas from electrical vehicles to mobile communications. While 2-dimensional systems like MoS2 are promising electrode materials due to their potentially high capacity, their poor ratecapability and low cycle-stability are severe handicaps. Here we study the electrical, mechanical and lithium storage properties of solution-processed MoS2/carbon nanotube anodes.Nanotube addition gives up to ×10 10 and ×40 increases in electrical conductivity and mechanical toughness respectively. The increased conductivity results in up to a ×100 capacity enhancement to ~1200 mAh/g (~3000 mAh/cm 3 ) at 0.1 A/g, while the improved toughness significantly boosts cycle stability. Composites with 20 wt% nanotubes combined high reversible capacity with excellent cycling stability (e.g. ~950 mAh/g after 500 cycles at 2 A/g) and high-rate capability (~600 mAh/g at 20 A/g). The conductivity, toughness and capacity scaled with nanotube content according to percolation theory while the stability increased sharply at the mechanical percolation threshold. We believe the improvements in conductivity and toughness obtained after addition of nanotubes can be transferred to other electrode materials such as silicon nanoparticles.Keywords: percolating, network, anode, mechanical 2 In recent years, lithium ion batteries (LIBs) have become the most common rechargeable power sources for portable electronic devices and electric vehicles. 1, 2 Nevertheless, they still suffer from several problems; their energy and especially power densities have not fulfilled their ultimate potential while their safety record is not unblemished. 3 A significant problem is that graphite, the dominant anode material used in LIBs, is limited by a relatively low theoretical capacity of 372 mAh/g. 4 As such, the development of the next-generation of LIBs, is expected to see the replacement of graphite-based anodes with alternative materials having higher capacity at similarly low cost. While a range of materials, including silicon, have been envisaged as future LIB anode materials, 4 of particular interest are 2-dimensional (2D) nanomaterials 5 such as graphene 6 and MoS2. 7 Over the last decade, 2D nano-materials have generated much excitement in the nanomaterials science community. [8][9][10] They come in many types including graphene, transition metal dichalcogenides (TMDs) and transition metal oxides (TMOs). These materials consist of covalently bonded monolayers which can stack via van der Waals interactions to form layered crystals. 8,9 Such 2D nanomaterials are often found as nanosheets with lateral size ranging from 10s of nm to microns and thickness of ~nm. 9 These materials have shown potential for applications 5 in both energy generation 11 and storage. 12 In the context of LIBs, exfoliated TMDs have received significant attention as prospective anode materials. 13,14 While bulk MoS2 was proposed 15 as a Li ion battery electrode material as early as 1980 due to its hi...

The search for high-capacity, low-cost electrode materials for sodium-ion batteries is a significant challenge in energy research. Among the many potential candidates, layered compounds such as MoS2 have attracted increasing attention. However, such materials have not yet fulfilled their true potential. Here, we show that networks of liquid phase exfoliated MoS2 nanosheets, reinforced with 20 wt % single-wall carbon nanotubes (SWNTs), can be formed into sodium-ion battery electrodes with large gravimetric, volumetric, and areal capacity. The MoS2/SWNT composite films are highly porous, electrically conductive, and mechanically robust due to its percolating carbon nanotube network. When directly employed as the working electrode, they exhibit a specific capacity of >400 mAh/g and volumetric capacity of ∼650 mAh/cm(3). Their mechanical stability allows them to be processed into free-standing films with tunable thickness up to ∼100 μm, corresponding to an areal loading of 15 mg/cm(2). Their high electrical conductivity allows the high volumetric capacity to be retained, even at high thickness, resulting in state-of-the-art areal capacities of >4.0 mAh/cm(2). Such values are competitive with their lithium-ion counterparts.

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Lithium–sulfur batteries are strongly expected to be the next-generation energy storage technology due to their superior theoretical specific capacity and energy density.

Lithium-sulfur (Li-S) batteries have attracted widespread attention due to their high theoretical energy density. However, their practical application is still hindered by the shuttle effect and the sluggish conversion of lithium polysulfides (LiPSs). Herein, monodisperse molybdenum (Mo) nanoparticles embedded onto nitrogen-doped graphene (Mo@N-G) were developed and used as a highly efficient electrocatalyst to enhance LiPS conversion. The weight ratio of the electrocatalyst in the catalyst/sulfur cathode is only 9%. The unfilled d orbitals of oxidized Mo can attract the electrons of LiPS anions and form Mo–S bonds during the electrochemical process, thus facilitating fast conversion of LiPSs. Li-S batteries based on the Mo@N-G/S cathode can exhibit excellent rate performance, large capacity, and superior cycling stability. Moreover, Mo@N-G also plays an important role in room-temperature quasi-solid-state Li-S batteries. These interesting findings suggest the great potential of Mo nanoparticles in building high-performance Li-S batteries.