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In this paper, we report a flame deposition method to prepare carbon nanoparticles (CNPs) from coconut oil. The CNPs were further modified with a piranha solution to obtain surfacecarboxylated carbon nanoparticles (c-CNPs). When used as an anode for sodium-ion batteries, the CNPs and c-CNPs respectively delivered discharge capacities of 277 and 278 mAhg-1 in the second cycle at a current density of 100 mAg-1. At the 20 th cycle, the capacities of CNP and c-CNPs were 217 and 206 mAhg-1 respectively. The results suggest that modification of the CNPs with the piranha solution improved neither the charge storage capacity nor the stability against cycling in a sodium-ion battery. When the CNP and c-CNP were used an anode in a lithium-ion battery, 2 nd-cycle discharge capacities of 741 and 742 mAhg-1 respectively at a current density of 100 mAg-1 were obtained. After 20 cycles the capacities of CNP and c-CNP became 464 and 577 mAhg-1 respectively, showing the cycling stability of the CNPs was improved after modification. The excellent cycling performance, high capacity and good rate capability make the present material as highly promising anodes for both sodium-ion and lithium-ion batteries.

kinetics of Mg 2+ in cathode materials due to the strong electrostatic interactions, thus limiting the capacity of the cathode materials. [4] One solution to solve this problem is to replace kinetically sluggish Mg 2+ intercalation/deintercalation with kinetically more efficient Li + using a dual salt electrolyte. [5] With this design, Li + intercalation/deintercalation occurs at the cathode with a fast kinetic rate, whereas the advantages of using Mg anode are retained since only magnesium deposition/dissolution occurs at the anode due to its high redox potential. [6] However, in such a hybrid battery system, the asymmetric use of Mg 2+ and Li + on each electrode requires a large amount of electrolyte as an ion reservoir to supply Li + and receive Mg 2+ during discharging and charging. Besides, the most commonly used Li salts in the Mg 2+ /Li + battery (MLIB) have either a limited solubility in solvent or a narrow electrochemical window, leading to a low efficiency. Therefore, it is desirable to develop a cathode that can accommodate both Mg 2+ and Li + .2D transition metal dichalcogenides (TMDCs) with weak interlayer van der Waals (vdW) interactions offer the privilege of introducing foreign atoms or molecules between the layers via an intercalation mechanism. [7] Among various TMCDs, molybdenum disulfide (MoS 2 ) with large interlayer spacing (0.62 nm) has been intensively investigated as an electrode material for rechargeable batteries. [8] Although bulk MoS 2 does not favor large Mg 2+ intercalations, the exfoliated MoS 2 with an increased interlayer spacing can largely improve Mg 2+ diffusion and storage. [9] Many methods can be applied to prepare exfoliated MoS 2 , such as mechanical cleavage, [10] liquid exfoliation, [7c,11] and electrochemical exfoliation. [12] Especially, the Li-intercalation exfoliated MoS 2 contains a high ratio of metallic 1T phase, which is in favor of various ion intercalation, including Mg 2+ . [9,13] Thus, controlling the cathode structure by enlarging the ion transport channel and maximizing the exposure of active edge sites is of paramount importance.Herein, we report the growth of interlayer expanded MoS 2 nanosheets on graphene foam (GF) via a hydrothermal method as cathodes for both, MRB and MLIB. The obtained freestanding MoS 2 /graphene foam composite (hereafter referred to as E-MG) displays an interlayer spacing of 1.01 nm (0.62 nm for Bulk-MoS 2 ) with a high ratio of metallic 1T phase. An MRB constructed using this cathode showed pronounced solid-state Mg 2+ diffusion and ion storage capacity than Bulk-MoS 2 . Further, a hybrid MLIB fabricated using the E-MG as cathode,The hybrid Mg 2+ /Li + battery (MLIB) is a very promising energy storage technology that combines the advantage of the Li and Mg electrochemistry. However, previous research has shown that the battery performance is limited due to the strong dependence on the Li content in the dual Mg 2+ /Li + electrolyte. This limitation can be circumvented by significantly improving the diffusion kinetics of Mg 2+ in...

Nitrogen-rich hard carbon with enhanced capacitive storage for room temperature sodium-ion battery is investigated. The presence of nitrogen allows stronger sodium ion interaction to realize high-performance batteries with a specific capacity of ∼204 mA h g−1 after 1000 cycles at 1 A g−1 current density.

Pyromellitic dianhydride-based polyimides [C 16 H 6 O 4 N 2 ] n with different crystallinity and morphology were synthesised by simple one-step hydrothermal method. The electrochemical performance and sodium storage mechanism of the polyimide-based organic electrode as anode for sodium-ion batteries were investigated.