Improved gravimetric energy density and cycle life in organic lithium-ion batteries with naphthazarin-based electrode materials

Abstract

Replacing the scarce metal-based positive electrode materials currently used in rechargeable lithium ion batteries with organic compounds helps address environmental issues and might enhance gravimetric electrochemical capacity. The challenge has been to find organic materials with both high capacity and long-cycle life. Here, we study the naphthazarin (5,8-dihydroxy-1,4-naphthoquinone) skeleton as a high capacity candidate electrode for lithium-ion batteries, showing a multielectron-transfer type redox reaction. We also use electron energy-loss spectroscopy to reveal the reaction stoichiometry during charge/discharge processes. While the lithium salt of naphthazarin itself helped deliver a high initial capacity, its cycle-life was not satisfactory. Instead, a newly synthesized naphthazarin-dimer shows a lengthened cycle-life without sacrificing the initial high capacity of 416 mAh g−1 and energy density of 1.1 Wh g−1.

Synthesis and Electrochemical Properties of Lignin-Derived High Surface Area Carbons

“…Measuring cycling performance is essential since it shows optimal charge/discharge rates for the most efficient capacity. Reasonable cycling parameters can minimize capacity fading, which leads to long cycling life of the energy storage system [59]. Figure 9a shows the performance of the HSAC material under various current densities, from 0.1 to 3.0 A•g −1 .…”

Emerging Lithiated Organic Cathode Materials for Lithium‐Ion Full Batteries

“…All-organic symmetric batteries use the same material as both the cathode and anode. [28,29,39,49] As shown in Figure 5b, the all-symmetric Li 4p-DHT j j Li 4 -p-DHT batteries deliver discharge capacities of 236, 222, 198, and 148 mAh g À 1 (based on the mass of Li 4 -p-DHT in the cathode) at current rates of 0.1, 0.5, 2, and 5 C, respectively. [49] All-organic asymmetric full batteries often use Li 2 TP or ADALS as the anode.…”

“…Specifically, the thermal decomposition temperatures of lithiated organic cathode materials are often higher than 300 °C under inert atmospheres. [29,33,39,40] For instance, TG measurements indicate the increased stability of Li 2 -Mn-p-DHT-MOF up to 500 °C, compared with H 2 -Mn-p-DHT-MOF which degraded at ca. 250 °C.…”

“…Theoretical calculations reveal that the dissolution can be alleviated by the strong intermolecular interaction (81 kJ mol À 1 ) of the Li 2 -DHNQ dimer, which is much greater than that of the pristine Li 2 -DHNQ (27 kJ mol À 1 ). [39] Salt formation through the introduction of À COOLi groups is another strategy at the molecule level to mitigate the dissolution problem and thus enhance the cycling stability of lithiated organic cathode materials. [28,29,35,38] For electrode-level optimization, introducing graphene or γ-Al 2 O 3 substrates to anchor lithiated organic cathode materials is a common method to enhance their cycling stability.…”

“…From the aspect of molecule design, polymerization, such as dimerization and the generation of metal–organic coordination polymers, was applied to limit the dissolution and thus improve the cycling stability of lithiated organic cathode materials [37, 39] . As shown in Figure 4a, the Li 2 ‐DHNQ dimer (DHNQ: 5,8‐dihydroxy‐1,4‐naphthoquinone) maintained 300 mAh g −1 after 100 cycles, which is much higher than that of the pristine Li 2 ‐DHNQ.…”