Enhanced Adsorption of Polysulfides on Carbon Nanotubes/Boron Nitride Fibers for High‐Performance Lithium‐Sulfur Batteries

Abstract

Lithium-sulfur (Li-S) batteriesa re one of the most promising high-energy-densitys torages ystems. However, seriousc apacity attenuation and poor cycling stability induced by the shuttlee ffect of polysulfide intermediates can impede the practical applicationo fL iS batteries. Herein we report an ovel sulfur cathode by intertwiningm ulti-walled carbon nanotubes (CNTs) and porous boron nitride fibers (BNFs) for the subsequentl oading of sulfur.T his structural design enablest rapping of active sulfur and serves to localize the soluble polysulfide within the cathode region, leading to low activem aterial loss. Compared with CNTs/S, CNTs/BNFs/S cathodes deliver ah igh initial capacity of 1222 mAh g À1 at 0.1 C. Upon increasing the current density to 4C,t he cell retained ac apacity of 482 mAh g À1 after 500 cyclesw ith ac apacity decay of only 0.044 %p er cycle. The designofCNTs/BNFs/S gives new insightonhow to optimize cathodesfor Li-S batteries.

Highly dispersed and functionalized boron nitride nanosheets contribute to ultra-stable long-life all-solid-state batteries

“…6c). In the Nyquist diagram, the semicircle of the high-frequency region and the intersection at a high frequency of the real axis represent charge transfer resistance ( R ct ) and ohm resistance ( R o ), 51–53 respectively. The low R ct and R o of CPE-3%-BNNSs reflect their high ion conductivity, which again effectively confirms the positive effect of BNNS additives.…”

Enhanced Performance of Li–S Batteries due to Synergistic Adsorption and Catalysis Activity within a Separation Coating Made of Hybridized BNNSs/N-Doping Porous Carbon Fibers

“…For the CV curves of the cell operated at 0.6 mV s –1 (Figure a), the reduction peaks of conversion of S 8 to LiPSs was observed at 2.31 V, while the peak of 1.99 V illustrated the process from LiPSs to the final discharging product of Li 2 S . Inversely, the oxidation potential that implied the conversion of insoluble Li 2 S to LiPSs was 2.36 V and LiPSs to the S 8 , was 2.41 V. Superior properties of almost free of offset for the first-four-cycle CV curves (Figure a) and the highest current value of 7.44 mA compared to other separators are displayed (Figure S16a–c in the Supporting Information), revealing an improved electrocatalytic activity toward sulfur oxidation/reduction due to the modification of BNNSs/CHFs. The abovementioned results are in agreement with the analyses of the symmetric cells (Figure c).…”

Boron‐Based High‐Performance Lithium Batteries: Recent Progress, Challenges, and Perspectives

“…The positive vacancies in BN nanosheets can immobilize and transform LiPS and accelerate the diffusion of Li ions, so that v-BNbased LSB has a high initial specific capacity of 1262 mAh g −1 at a current density of 0.1 C, and the capacity remains 770 mAh g −1 after 150 cycles. Li et al [193] successfully designed a novel cathode material by interweaving multiwalled carbon nanotubes (CNTs) and boron nitride fibers (BNFs) and loading them with sulfur (Figure 16b). The new cathode material (CNTs/BNFs/S) has a very high initial specific capacity and can greatly improve the cycling stability due to its interwoven structure that can effectively load sulfur active material and trap LiPS in the cathode region.…”

“…Li et al. [ 193 ] successfully designed a novel cathode material by interweaving multiwalled carbon nanotubes (CNTs) and boron nitride fibers (BNFs) and loading them with sulfur (Figure 16b). The new cathode material (CNTs/BNFs/S) has a very high initial specific capacity and can greatly improve the cycling stability due to its interwoven structure that can effectively load sulfur active material and trap LiPS in the cathode region.…”

“…b) Schematic diagram of synthetic route of CNTs/BNFs/S electrode. Reproduced with permission [193]. Copyright 2020, Wiley-VCH.…”