Lithium Benzenedithiolate Catholytes for Rechargeable Lithium Batteries

Abstract

Organic electrode materials have become a vibrant area of research. Lithium benzenedithiolate (LBDT) consists of two -SLi groups that could donate 2Li + and 2e − in oxidation reactions, thus being a potential high-capacity organic cathode material for rechargeable lithium batteries. Herein, 1,2-, 1,3-, and 1,4-LBDTs are investigated to elucidate the relationship of their redox chemistry and effect of lithium thiolate position on their electrochemical behavior experimentally and theoretically. High-performance liquid chromatography in tandem with quadrupole time-of-flight mass spectrometry is used, for the first time, to separate and identify the charge and discharge products of these compounds in lithium batteries. During the charging process, 1,2-, 1,3-and 1,4-LBDTs are mainly converted to the cyclic dimer, trimer, and tetramer respectively. While in the discharge process, the initial lithiated materials are recovered. The cyclic dimer of 1,2-LBDT shows the lowest discharge overpotential and fast kinetics, which are related to the easiness of the 2nd lithiation process. It delivers an initial specific capacity of 340 mAh g −1 and retains 84.1% of the initial capacity over 100 cycles at C/2 rate. In addition, it shows much better rate capability than the other two LBDTs. The structure-performance relationship of LBDT in lithium batteries is correlated.

An Organic–Inorganic Hybrid Cathode Based on S–Se Dynamic Covalent Bonds

“…Thehybrid cathode prepared in this manner allows Se and DPTS to be physically trapped within the CNT network, reducing dissolution of the discharge products and inhibiting the shuttle effect. [14] As shown in the Supporting Information, Figures S4, the sulfur element is uniformly distributed in the Se/CNTs composite electrode.T he electrochemical performance of the DPTS-Se hybrid cathode is evaluated in Li half cells.The initial discharge-charge voltage profile of aLi/DPTS-Se cell is shown in Figure 1C.Itcan be seen that as lope voltage region at about 2.30 Va ppears during the first discharge,w hich is probably due to the formation of PhSSLi, [4a] PhSLi, and Li 2 Se 8 .I nt he following process,the DPTS-Se cathode exhibits two discharge plateaus at 2.05 and 1.95 V, [15] which are attributed to the formation of Li 2 Sand Li 2 Se.F or comparison, the discharge/charge profiles of Se and DPTS cathodes are also shown in Figure 1C.The Se electrode exhibits standard two discharge voltage regions at 2.15 Vand 2.02 V. TheDPTS electrode shows avoltage slope and plateau. Clearly,t he DPTS-Se hybrid electrode has the voltage characteristics of both Se and DPTS materials.…”

An Organic–Inorganic Hybrid Cathode Based on S–Se Dynamic Covalent Bonds

“…The DPTS/Se molar ratio is 1:1. The hybrid cathode prepared in this manner allows Se and DPTS to be physically trapped within the CNT network, reducing dissolution of the discharge products and inhibiting the shuttle effect . As shown in the Supporting Information, Figures S4, the sulfur element is uniformly distributed in the Se/CNTs composite electrode.…”

Advances of Organosulfur Materials for Rechargeable Metal Batteries

“…Li et al investigated three lithium benzenedithiolate (LBDT) isomers, i.e., 1,2‐LBDT, 1,3‐LBDT, and 1,4‐LBDT. [ 13 ] The sulfur bonding sites have profound effects on the recharged products and their electrochemical behavior in lithium batteries. 1,2‐LBDTs are mostly converted to dimers in the charge, 1,3‐LBDTs are converted to trimers and tetramers, and 1,4‐LBDT are primarily converted to tetramers because of the different stability energy of the charged products, as shown in Figure 2 a .…”