Hydrogen Stabilization and Activation of Dry-Quenched Coke for High-Rate-Performance Lithium-Ion Batteries.

Lithium-ion batteries (LIBs) have rapidly come to dominate the market owing to their high power and energy densities. However, several factors have considerably limited their widespread commercial application, including high cost, poor high-rate performance, and complex synthetic conditions. Herein, we use earth-abundant and low-cost dry-quenched coke (DQC) to prepare low-crystalline carbon as anode material for LIBs and tailor the carbon skeleton via a facile green and sustainable hydrogen treatment. In particular, DQC is initially pyrolyzed at 1000 °C, followed by hydrogen treatment at 600 °C to obtain C-1000 H2-600. The resultant C-1000 H2-600 possesses abundant active defect sites and oxygen functional groups, endowing it with high-rate capabilities (C-1000 H2-600 vs. commercial graphite: 223.98 vs. 198.5 mAh g-1 at 1 A g-1 with a capacity retention of about 72.79% vs. 58.05%, 196.97 vs. 109.1 mAh g-1 at 2 A g-1 for 64.01% vs. 31.91%), and a stable cycling life (205.5 mAh g-1 for 1000 cycles at 2 A g-1) for LIBs. This proves that as a simple moderator, hydrogen effectively tailors the microstructure and surface-active sites of carbon materials and transforms low-cost DQC into high-value advanced carbon anodes by a green and sustainable route to improve the lithium storage performance.

Constructing Heterostructured Bimetallic Selenides on an N-Doped Carbon Nanoframework as Anodes for Ultrastable Na-Ion Batteries.

Transition-metal selenides have been recognized as a class of promising anode materials for sodium-ion batteries (SIBs) on account of their high capacity. Nevertheless, the sluggish conversion kinetics and rapid capacity decay caused by insufficient conductivity and volume change restrain their applications. Herein, hollow heterostructured bimetallic selenides embedded in an N-doped carbon nanoframework (H-CoSe2/ZnSe@NC) were prepared via a facile template-engaged method. Benefiting from the rich defect at the phase boundary of the CoSe2/ZnSe heterostructure, pre-reserved cavity, and enhanced structure rigidity, the abovementioned issues are resolved at once, and the accelerated charge transportation kinetics traced by spectroscopy techniques and theoretical calculations certify the interface effect in the capacity release. In addition, ex situ X-ray photoelectron spectroscopy, X-ray diffraction, and high-resolution transmission electron microscopy all confirm the high-reversible electrochemical conversion mechanism in H-CoSe2/ZnSe@NC. Together with a reasonable structural architecture and the highly reversible conversion reaction, H-CoSe2/ZnSe@NC displays a prominent rate capacity (244.8 mA h g-1 at 10 A g-1) as well as an ultralong lifespan (10,000 cycles at 10 A g-1), highlighting the significance of structure control in fabricating high-performance anodes for SIBs.