RESUMO
Lithium sulfur batteries (Li-S) have been deemed to be the promising energy-storage systems. Nevertheless, the shuttle effect caused by diffusion of polysulfides limit their application. In this work, the different dimensions of g-C3N4 nanomaterials (2D g-C3N4 nanosheets and 3D g-C3N4 nanomesh) were doped in S electrode. Because of the large specific surface area of 3D g-C3N4 nanomesh and strong chemical adsorption of polysulfides can provide better effect for inhibition of shuttling effect and its proper electron passage make electrochemical kinetics of lithium-sulfur battery enhanced. The discharge specific capacity of the 3D g-C3N4 battery is up to 731 mAh/g and longer cycling performance with 540 mAh/g after 180 cycles. This experiment paves the way forward for the application of g-C3N4 on Li-S batteries.
RESUMO
Nowadays, lithium (Li) metal batteries arouse widespread concerns due to its ultrahigh specific capacity (3,860 mAh g-1). However, the growth of Li dendrites has always limited their industrial development. In this paper, the use of concentrated electrolyte with lithium difluoro(oxalate)borate (LiODFB) salt in 1, 2-dimethoxyethane (DME) enables the good cycling of a Li metal anode at high Coulombic efficiency (up to 98.1%) without dendrite growth. Furthermore, a Li/Li cell can be cycled at 1 mA cm-2 for over 3,000 h. Besides, compared to conventional LiPF6-carbonate electrolyte, Li/LiFePO4 cells with 4 M LiODFB-DME exhibit superior electrochemical performances, especially at high temperature (65°C). These outstanding performances can be certified to the increased availability of Li+ concentration and the merits of LiODFB salt. We believe that the concentrated LiODFB electrolyte is help to enable practical applications for Li metal anode in rechargeable batteries.
RESUMO
Lithium ion batteries with graphite negative electrodes have been developed to date due to their low power density, which limits their application in many cases, however. Nanoscale Li4Ti5O12 has higher power density than conventional graphite anode materials. In order to ensure that the full-cell system has high power and high energy, cathode materials are very important. In this paper, three different cathode materials, LiNi0.8Co0.15Al0.05O2 (NCA), LiNi0.6Co0.2Mn0.2O2 (NCM622), and LiCoO2 (LCO), were used to conduct a comprehensive study, and optimal NCA-Li4Ti5O12(LTO) full battery system was selected under high power conditions. On the basis, in order to further increase battery power density, and in combination with the mechanism of the supercapacitor non-Faradic energy storage, polyaniline activated carbon material (PANI-AC) with excellent capacitance characteristics was prepared. In the end, we proposed a new type of hybrid battery capacitor system with high power and high energy.
