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and canwithstand a thousand cycles, maintaining 61% of its original capacity. We demonstrate that copper can enable not only high voltage,but also excellent stability. This work opens up a new avenue of oxide design for high energy, cost effective battery systems.© The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative CommonsAttribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/),which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in anyway and is properly cited. For permission for commercial reuse, please email: oa@electrochem.org. [DOI: 10.1149/2.0041505eel]All rights reserved.Manuscript submitted February 4, 2015; revised manuscript received March 4, 2015. Published March 19, 2015.

An architecture featuring carbon coated, interconnected nano-grains constructed with mesopores is developed for LiMnPO 4 cathode material. This architecture facilitates enhanced lithium ionic and electronic transports; favours improved lithium storage performance. Mesoporous LiMnPO 4 /C electrode delivers discharge capacity of 140 mAh g −1 at 0.05 C using galvanostatic cycling mode. This best electrochemical response of LiMnPO 4 /C at constant current mode is complemented by diffusion studies using cyclic voltammetry and impedance spectroscopy. Further, the interdependence of lithium storage performance on carbon content, milling time (2, 4, 6 and 10 h), grain size and porous characteristics (surface area, pore size and pore volume) is also discussed. Finally, the feasibility of LiMnPO 4 /C cathode is evaluated against Li 4 Ti 5 O 12 /C anode in a full cell.

Sodium storage in α-MoO3 anode material is reported here for the first time. Upon cycling in the voltage window 0.04–3.0 V, MoO3 anode delivers first cycle sodiation and desodiation capacities of 771 and 410 mAh g−1. The average sodiation and desodiation potentials of the stable cycles lie below 1.0 V with attractive voltage profiles. MoO3 anode also shows favorable rate performance and long cycle life over 500 cycles. Keywords: Sodium-ion battery, Anode material, Conversion reaction, High rate performance, Long term cyclability, Full cell testing

Sodium ion batteries are attractive for the rapidly emerging large-scale energy storage market for intermittent renewable resources. Currently a viable cathode material does not exist for practical non-aqueous sodium ion battery applications. Here we disclose a high performance, durable electrode material based on the 3D NASICON framework. Porous Na3V2(PO4)3/C was synthesized using a novel solution-based approach. This material, as a cathode, is capable of delivering an energy storage capacity of ∼400 mWh/g vs. sodium metal. Furthermore, at high current rates (10, 20 and 40 C), it displayed remarkable capacity retention. Equally impressive is the long term cycle life. Nearly 50% of the initial capacity was retained after 30,000 charge/discharge cycles at 40 C (4.7 A/g). Notably, coulombic efficiency was 99.68% (average) over the course of cycling. To the best of our knowledge, the combination of high energy density, high power density and ultra long cycle life demonstrated here has never been reported before for sodium ion batteries. We believe our findings will have profound implications for developing large-scale energy storage systems for renewable energy sources.

Utilization of a novel two-dimensional coordination polymer generated from a trinuclear building block [Cu3(HSser)3(H2O)2]·2H2O (1) as a precursor in the synthesis of copper sulfide serendipitously...

Nanorods of the title compound are synthesized from a mixture of Na(OAc), Ti(O-iPr)4, and hexadecyl-trimethyl-ammonium bromide in H2O and EtOH, followed by sintering of the obtained powder in air at 800 °C for 6 h.

The ultra-fast (30C or 2 min) rate capability and impressive long cycle life (>5000 cycles) of Na2Ti6O13 are reported. A stable 2.5 V sodium-ion battery full cell is demonstrated. In addition, the sodium storage mechanism and thermal stability of Na2Ti6O13 are discussed.

Metal organic phosphate open framework materials (III), (V), and (VII) are investigated as hybrid cathode materials for lithium ion batteries.

Metal organic phosphate open framework materials (III), (V), and (VII) are investigated as hybrid cathode materials for lithium ion batteries.

Nanostructured materials have triggered a great excitement in recent times due to both fundamental interest as well as technological impact relevant for lithium ion batteries (LIBs). Size reduction in nanocrystals leads to a variety of unexpected exciting phenomena due to enhanced surface-to-volume ratio and reduced transport length. We will consider a few examples of nanostructured electrode materials in the context of lithium batteries for achieving high storage and high rate performances. 1. LiFeP0 4 nanoplates synthesized using solvothermal method could store Li-ions comparable to its theoretical capacity at C/10, while at 30C, they exhibit storage capacity up to 45 mAh/g. Size reduction (~30 nm) at the b-axis favors the fast Li-ion diffusion. In addition to this, uniform ~5 nm carbon coating throughout the plates provides excellent electronically conducting path for electrons. This nano architecture enables fast insertion/extraction of both Li-ions as well as electrons. 2. Mesporous-TiO 2 with high surface area (135m 2 /g) synthesized using soft-template method exhibits high volumetric density compared to commercial nanopowder (P25), with excellent Li-storage behavior. C16 meso-TiO 2 synthesized from CTAB exhibits reversible storage capacity of 288mAh/g at 0.2C and 109 mAh/g at 30C. 3. Zero strain Li 4 Ti 5 O 12 anode material has been synthesized using several wet chemical routes; the best condition has been optimized to achieve storage capability close to theoretical limit of 175mAh/g at C/10. At 10C, we could retain lithium storage up to 88 mAh/g. 4. We report our recent results on α-Fe 2 O 3 and γ-Fe 2 O 3 using conversion reaction, providing insight for a better storage capability in γ-phase than the α-phase at 2C resulting solely from the nanocrystallinity.

Here we report TiO2, in the bronze phase (TiO2-B), with a porous nanostructure designed for rapid lithium storage and charge transfer. A new synthesis method is described that not only facilitates these improvements, but also removes the requirement for an autoclave, which is usually common in the synthesis of this material. Most notably, peak capacities of 235, 148, and 66 mAh g−1 at 0.2 C, 20 C, and 100 C were attained, respectively. These results were achieved with low conductive carbon contents (5%). In addition, recent atomistic reports on TiO2-B were correlated with these results in order to explain how the morphology reported here was leveraged in order to attain high performance. Diffusion coefficients were also calculated for this novel TiO2-B architecture and found to be in good agreement with a previous study performed using NMR.

Identifying dual role electrode materials capable of storing both lithium and sodium are thought to be highly relevant, as these materials could find potential applications simultaneously in lithium and sodium ion batteries. In this regard, the concept of dual alkali storage is demonstrated in Fe(3)O(4) anode material undergoing conversion reaction. To enable improved storage, a rational active material and electrode design is proposed. Accordingly, the following features were simultaneously incorporated into the design: (i) an optimal particle size, (ii) a conducting matrix, (iii) adequately large active material surface area and (iv) strong electrode material-current collector integrity. Electrodes incorporating this rational design exhibit excellent high rate performance and impressive cyclability during lithium storage. For instance, Fe(3)O(4) electrodes deliver a charge capacity of 950 mAh g(-1) at 1.2 C (~2.6 times higher than graphite and 5.4 times higher than Li(4)Ti(5)O(12)). Further, these electrodes show no signs of capacity fade even up to 1100 cycles. Impressively, the cells could also be charged-discharged to 65% of their theoretical capacity in just 5 min or 12 C (11.11 A g(-1)). The rate performance and cyclability of lithium storage achieved here are amongst the highest reported values in the literature for the conversion reaction in Fe(3)O(4). Besides lithium storage, the dual role of this anode is shown by demonstrating its sodium storage ability by conversion reaction for the first time.

We report here the electrochemical properties of Na2Ti3O7, a potential non-carbon based, low-voltage anode material for room temperature sodium ion battery applications. A solid-state route was used to prepare Na2Ti3O7. Further, XRD, SEM, TEM, HRTEM, SAED, XPS and EDX techniques were used to characterize the material. The Na/Na2Ti3O7 cell displayed a charge capacity of 177 mA h g−1 at 0.1 C rate. High rate and long term cyclic performance at different rates showed relatively stable storage capacities. Surprisingly, if the lower cut-off voltage is altered, the appearance of a new charge plateau is seen, with no apparent change in the discharge behaviour. The kinetics of sodium insertion and extraction are discussed utilizing CV and EIS techniques. We also report the sodium chemical diffusion coefficient of the Na2Ti3O7/CB electrode estimated using GITT.

A simple solvothermal method was used to synthesize nanoplates of LiMnPO4 (LMP) with a thickness of ∼60 to 80 nm. The LMP nanoplates were well characterized by PXRD, SEM and HRTEM techniques. The reaction conditions for the solvothermal method were found to be crucial to control the morphology of LMP. Carbon, silver, gold and copper have been coated on the surfaces of LMP nanoplates to improve the electronic conductivity. Despite such coating, the electrochemical activity of such metal-decorated LMP nanoplates was found to be minimal due to discontinuous wiring limiting the electronic conduction. Therefore, the Mn2+ in the nanoplates was partially substituted by the Fe2+ ion to obtain the following composition [LiMnxFe1−xPO4 (x = 0.5 and 0.75)]. These solid solutions showed excellent storage performance compared to pure LMP. Especially LiMn0.5Fe0.5PO4/C nanoplates exhibited a reversible capacity of 153, 121, 91 and 31 mA h g−1 at 0.02, 0.1, 5 and 18 C respectively. In addition, LiMn0.5Fe0.5PO4/C also demonstrated a stable long term cycling capacity of 103 mA h g−1 at a 2 C rate up to 1000 cycles.

Micrometre-sized mesoporous materials have characteristic grains as well as pores nearly in the same scale. Electrodes of mesoporous materials for lithium batteries have short transport lengths for Li+ ions due to their nano-sized grains (10–20 nm), and easy access for electrolytes due to their nanopores (5–10 nm). Such mesoporous materials have high packing densities unlike nanopowders, nanowires, nanorods and nanotubes. Despite such advantages, electronic conduction over micrometre-sized particles limits the rate performance of mesporous materials. Occasionally counductive thin layers (2–5 nm) of carbon or RuO2 have been used to overcome such kinetic limitations and to achieve high storage performances. In this manuscript, we present a simple approach for the synthesis of mesoporous TiO2 anatase using a soft-template method, which shows superior storage performance without such conductive surface layers. Various cationic surfactants with different chain lengths have been selected for this investigation to assist the formation of the mesoporous TiO2 structure. Among these, cetyl trimethylammoniumbromide templated C16-TiO2 has the highest surface area of 135 m2 g−1 and reversible capacity of 288, 220, 138,134 and 107 mAh g−1 at 0.2, 1, 5, 10 and 30C respectively. The storage performance of the as-synthesized mesoporous TiO2 is nearly five times better than the commercially available TiO2 nanopowder. The packing density of meso-TiO2 is found to be 6.6 times higher than the TiO2 nanopowder. In addition, battery testing using mesoporous TiO2 electrodes without the 15% carbon additive exhibits nearly the same performance at low rate as the meso-TiO2 with carbon additives. These exciting results suggest a facile conduction path for electrons, a unique character of micrometre-sized mesoporous TiO2 with highly interconnected nanograins of 15–20 nm.

In this manuscript, a systematic investigation on the electrochemical performance of as-synthesized metal organic framework (MOF) Zn3(HCOO)6 with diamondoid structure for the Li storage using conversion reaction at low potential is described. Nearly an invariable capacity of 560 mAh g−1 (9.6 moles of Li) was obtained up to 60 cycles at 60 mA g−1 within the voltage range 0.005–3.0 V. The regeneration of the MOF during the cycling and the improved cyclability are evidenced from the electrochemical results along with ex situ PXRD, FTIR and TEM studies. The electrochemical cycling suggests that metal formate frameworks react reversibly with Li through conversion reaction. The matrix involved during the cycling was lithium formate rather than the typical Li2O and this is well supported by the ex situ FTIR results. The thermodynamic feasibility to transform the lithium formate to transition metal formate is more highly favored than from Li2O and this is further confirmed by reacting lithium formate with respective transition metal nitrates. The reversible formation or regeneration of FOR1 MOF plays a vital role in attaining the superior Li storage performance. Ultimately, the observation of improved storage performance and good cycling stability of Co3(HCOO)6 and Zn1.5Co1.5(HCOO)6, and the overall simple and eco-friendly synthesis method demonstrates that robust, thermally stable MOFs are a prospective class of electrode materials for Li ion batteries (LIBs).

We report here on the lithium storage performance of α- and γ-Fe 2 O 3 , undergoing conversion reaction at C/10 and 2C. Both α-and γ-Fe 2 O 3 transform to nanostructured Fe/Li 2 O composite during the first discharge, while the first charge results in the formation of nanosized γ-Fe 2 O 3 . Such a transition from α-Fe 2 O 3 to γ-Fe 2 O 3 is attributed to its thermodynamics at the nanosize. Better storage performance of γ-Fe 2 O 3 at 2C compared with α-Fe 2 O 3 is attributed to the formation of highly crystalline, nanosized γ-Fe 2 O 3 . Apart from the reported inherent electronic conductivity of α-Fe 2 O 3 , the thermodynamics at the nanosize is also found to be one of the rate-limiting factors.

Lithium iron phosphate, LiFePO4 (LFP), is considered to be a potential cathode material for lithium-ion batteries but its rate performance is significantly restricted by sluggish kinetics of electrons and lithium ions. A simple solvothermal method has been described in this article to synthesize carbon coated LFP (LFP/C) nanoplates with varying thickness from 20 to 500 nm by using different iron precursors. The influence of solvents on the morphology of the LFP in the solvothermal synthesis is also investigated. A uniform carbon coverage at the surfaces has been achieved by a selective chelating carbonising source, D-gluconic acid lactone. The smallest dimension of the nanoplates has been found to be the b-axis where the Li+ ion diffuses quickly. The overall capacity and rate performance have, in general, been found to increase with the decrease of thickness of the nanoplates. Hierarchical LFP/C with ∼30 nm thickness shows the best electrochemical performance of 167 mA h g−1, followed by spindle (