Selenium/interconnected porous hollow carbon bubbles composites as the cathodes of Li–Se batteries with high performance

Abstract

A kind of Se/C nanocomposite is fabricated by dispersing selenium in interconnected porous hollow carbon bubbles (PHCBs) via a melt-diffusion method. Such PHCBs are composed of porous hollow carbon spheres with a size of ∼70 nm and shells of ∼12 nm thickness interconnected to each other. Instrumental analysis shows that the porous shell of the PHCBs could effectively disperse and sequester most of the selenium, while the inner cavity remains hollow. When evaluated as cathode materials in a carbonate-based electrolyte for Li-Se batteries, the Se/PHCBs composites exhibit significantly excellent cycling performance and a high rate capability. Especially, the Se/PHCBs composite with an optimal content of ∼50 wt% selenium (Se50/PHCBs) displays a reversible discharge capacity of 606.3 mA h g(-1) after 120 cycles at 0.1 C charge-discharge rate. As the current density increased from 0.1 to 1 C (678 mA g(-1)), the reversible capacity of the Se50/PHCBs composite can still reach 64% of the theoretical capacity (431.9 mA h g(-1)). These outstanding electrochemical features should be attributed to effective sequestration of Se in the PHCBs, as well as to the ability to accommodate volume variation and enhance the electronic transport by making Se have close contact with the carbon framework.

A New Salt‐Baked Approach for Confining Selenium in Metal Complex‐Derived Porous Carbon with Superior Lithium Storage Properties

“…Figure a shows the cyclic voltammetry (CV) curves of the Se electrode in the voltage range of 1.0–3.0 V at a sweep rate of 0.1 mV s −1 for the first five cycles. Based on previous reports, the electrochemical behavior of assembled Li‐Se batteries differs depending on the preparation process, the porous carbon hosts, and the electrolytes used . In the first discharging process, two strong peaks at around 1.75 and 1.9 V were observed, which may be related to the lithiation of different Se molecules in the Se/MnMC‐B composites .…”

“…The synthesis of selenium–carbon composites can be classified into three main categories: 1) melt‐diffusion strategy in a tubular furnace under argon atmosphere flow, 2) melt‐diffusion strategy in a sealed vessel under argon atmosphere or in vacuum . Normally, in these two approaches, pristine Se is pre‐milled together with the host porous carbon materials and then heated at around 260 °C.…”

Encapsulating selenium into macro-/micro-porous biochar-based framework for high-performance lithium-selenium batteries

“…4c), while that of Se 3d presents a Se 3d 5/2 peak at 54.94 eV and a 3d 3/2 peak at 55.89 eV (Fig. 4d) [14,[48][49][50][51]. By fitting, the C 1s XPS spectrum proves the minor of C=O and O-C=O functional groups co-existing with the major C-C chains, suggesting a possible interaction between the penetrated chains of elemental selenium and the surface of porous carbon matrix (Fig.…”

“…Se/MMPBc composite was prepared via a melt-diffusion method [9,[46][47][48]. At first, powdered selenium and a MMPBc sample were ground in an agate mortar at the fixed Se : MMPBc weight ratio of 6 : 4.…”

Metal Oxide Interlayer for Long‐Lived Lithium–Selenium Batteries

“…For a Se/CMK‐3 porous carbon hybrid, an initial capacity of 900 mA h g Se −1 decreased to 600 mA h g Se −1 after 50 cycles at 0.1 C rate . Another report on a cell with a Se/C‐bubbles hybrid, operated at the same rate, revealed an initial capacity of 691 mA h g Se −1 , which dropped to 605 mA h g Se −1 after 100 cycles. A Se/CNT hybrid showed a capacity of 400 mA h g Se −1 , which declined to 315 mA h g Se −1 after 100 cycles.…”