Improved cycling performance of polypyrrole coated potassium trivanadate as an anode for aqueous rechargeable lithium batteries

Layered BaV6O16·3H2O@GO as a high performance cathode material for calcium ion batteries

The lack of suitable cathode materials has hampered the further development of calcium-ion batteries (CIBs). A novel composite cathode material, namely BaV6O16·3H2O@GO, was fabricated, which delivers a high specific capacity of 285.72 mA h g-1 at 50 mA g-1 after 50 cycles and a long cycle life, benefiting from a large layer spacing and robust structure. This study provides guidance for the development of vanadium-based cathode materials for CIBs.

De-Ammonium Ba0.18V2O4.95/NH4V4O10 Film Electrodes as High-Performance Cathode Materials for Magnesium-Ion Batteries

Magnesium-ion batteries (MIBs) have been pushed into the research boom in the post-lithium-ion batteries era due to their low cost, no dendrite hazard, and high capacity. However, finding suitable cathode materials to improve the slow kinetics of Mg2+ is an ongoing challenge. In this work, Ba0.18V2O4.95/NH4V4O10 film electrodes were grown in one step on indium tin oxide (ITO) conductive glass using a low-temperature liquid-phase deposition method. Temperature was used as the probe condition, and it was concluded that the films annealed at 400 °C had suitable crystallinity and de-ammonium lattice space. At lower current density, with 0.5 M Mg(ClO4)2/PC as the electrolyte, it exhibited an initial discharge capacity of 130.99 mA h m-2 at 210 mA m-2 and 106.52% capacity retention after 100 cycles. In addition, it exhibited excellent electrochemical performance in long-term cycling (92.98% capacity retention after 300 cycles at 600 mA m-2). According to the results of ex situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM), the removal of NH4+ created more lattice space, assisting Ba0.18V2O4.95 to increase the transfer channels of Mg2+, providing more active sites to promote diffusion kinetics (the average DMg2+ was 2.07 × 10-12 cm2 s-1) and specific capacity. Therefore, these film electrodes for scalable Mg2+ storage are promising MIB cathode candidates that exhibit good performance advantages in storage applications.

Evaluating R&D efficiency of China’s listed lithium battery enterprises

Promoting the growth of the lithium battery sector has been a critical aspect of China’s energy policy in terms of achieving carbon neutrality. However, despite significant support on research and development (R&D) investments that have resulted in increasing size, the sector seems to be falling behind in technological areas. To guide future policies and understand proper ways of promoting R&D efficiency, we looked into the lithium battery industry of China. Specifically, data envelopment analysis (DEA) was used as the primary approach based on evidence from 22 listed lithium battery enterprises. The performance of the five leading players was compared with that of the industry as a whole. Results revealed little indication of a meaningful improvement in R&D efficiency throughout our sample from 2010 to 2019. However, during this period, a significant increase in R&D expenditure was witnessed. This finding was supported, as the results showed that the average technical efficiency of the 22 enterprises was 0.442, whereas the average pure technical efficiency was at 0.503, thus suggesting that they were suffering from decreasing returns to scale (DRS). In contrast, the performance of the five leading players seemed superior because their average efficiency scores were higher than the industry’s average. Moreover, they were experiencing increasing scale efficiency (IRS). We draw on these findings to suggest to policymakers that supporting technologically intensive sectors should be more than simply increasing investment scale; rather, it should also encompass assisting businesses in developing efficient managerial processes for R&D.