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Sulfur is a promising cathode material with a high theoretical capacity of 1672 mAh g-1, but the challenges of the low electrical conductivity of sulfur and the high solubility of polysulfide intermediates still hinder its practical application. In this work, we design and synthesize a special carbon black nanoparticle-sulfur composite cathode material (NCB-S@NCB) with a novel structure and a high sulfur content of 84 wt% for lithium-sulfur battery application. The NCB-S@NCB composite cathode delivers a high initial discharge capacity of 1258 mAh g-1 and still maintains a reversible capacity of 865 mAh g-1 after 100 cycles with a relatively constant Coulombic efficiency around 98.0%. © 2015 Elsevier B.V. All rights reserved.

Novel sulfur-rich polymeric materials were readily prepared via facile solution vulcanization of the commercial butadiene rubber (BR) and sulfur element, and were investigated as cathode materials for lithium-sulfur batteries. During the solution vulcanization procedure, the double bonds (C=C) in butadiene rubber are chemically cross-linked with sulfur. Moreover, the sulfur canalso self-polymerize into polymeric sulfur with long molecular chain. The polymeric sulfur chains penetrate into the crosslinked BR network to form a unique semi-internal penetration network (semi-IPN) confinement structure, which can effectively alleviate the dissolution and diffusion of intermediate polysulfide into electrolytes. Meanwhile, the obtained sulfur-rich polymeric composites have high sulfur contents even over 90%. As a result, the as-prepared sulfur-rich polymeric composites (BR-SPC) with network confine caged structure exhibit excellent cycling stability and high coulombic efficiency. An initial discharge specific capacity of 811 mA h g(-1) is reached, and retains 671 mA h g(-1) after 50 cycles at 0.1 C. The capacity retention rate and coulombic efficiency are 83%, 100%, respectively. Additionally, Super P (carbon black) was added in situ before vulcanization to increase the conductivity of BR-SPC composites. The BR-SPC composite containing Super P (BR-SPC-SP) reveals higher capacity retention of 85% over 50 cycles at 0.5 C than the BR-SPC composite without Super P.

Sulfur is a promising cathode material with a high theoretical capacity of 1672 mAh g-1, but the challenges of the low electrical conductivity of sulfur and the high solubility of polysulfide intermediates still hinder its practical application. In this work, we design and synthesize a special carbon black nanoparticle-sulfur composite cathode material (NCB-S@NCB) with a novel structure and a high sulfur content of 84 wt% for lithium-sulfur battery application. The NCB-S@NCB composite cathode delivers a high initial discharge capacity of 1258 mAh g-1 and still maintains a reversible capacity of 865 mAh g-1 after 100 cycles with a relatively constant Coulombic efficiency around 98.0%. © 2015 Elsevier B.V. All rights reserved.

Novel sulfur-rich polymeric materials were readily prepared via facile solution vulcanization of the commercial butadiene rubber (BR) and sulfur element, and were investigated as cathode materials for lithium-sulfur batteries. During the solution vulcanization procedure, the double bonds (C=C) in butadiene rubber are chemically cross-linked with sulfur. Moreover, the sulfur canalso self-polymerize into polymeric sulfur with long molecular chain. The polymeric sulfur chains penetrate into the crosslinked BR network to form a unique semi-internal penetration network (semi-IPN) confinement structure, which can effectively alleviate the dissolution and diffusion of intermediate polysulfide into electrolytes. Meanwhile, the obtained sulfur-rich polymeric composites have high sulfur contents even over 90%. As a result, the as-prepared sulfur-rich polymeric composites (BR-SPC) with network confine caged structure exhibit excellent cycling stability and high coulombic efficiency. An initial discharge specific capacity of 811 mA h g(-1) is reached, and retains 671 mA h g(-1) after 50 cycles at 0.1 C. The capacity retention rate and coulombic efficiency are 83%, 100%, respectively. Additionally, Super P (carbon black) was added in situ before vulcanization to increase the conductivity of BR-SPC composites. The BR-SPC composite containing Super P (BR-SPC-SP) reveals higher capacity retention of 85% over 50 cycles at 0.5 C than the BR-SPC composite without Super P.

Sulfur is a promising cathode material with a high theoretical capacity of 1672 mAh g-1, but the challenges of the low electrical conductivity of sulfur and the high solubility of polysulfide intermediates still hinder its practical application. In this work, we design and synthesize a special carbon black nanoparticle-sulfur composite cathode material (NCB-S@NCB) with a novel structure and a high sulfur content of 84 wt% for lithium-sulfur battery application. The NCB-S@NCB composite cathode delivers a high initial discharge capacity of 1258 mAh g-1 and still maintains a reversible capacity of 865 mAh g-1 after 100 cycles with a relatively constant Coulombic efficiency around 98.0%. © 2015 Elsevier B.V. All rights reserved.

Sulfur has a very high theoretical specific capacity of 1672 mA h g(-1) when used in lithium-sulfur batteries. However, the particularly rapid capacity reduction owing to the dissolution of intermediate polysulfide anions into the electrolyte still hinders practical application. In this respect, we report a novel core-shell structured sulfur-poly(sodium p-styrenesulfonate) (S@PSS) composite cathode material with a sulfur content as high as 93 wt% for lithium-sulfur batteries, which is the highest sulfur content disclosed in the literature. Due to the effective transport of lithium cations while blocking polysulfide anions by common ion Coulombic repulsion of the negatively charged -SO3- groups in the PSS protective layer, the S@PSS composite cathode exhibits a high initial specific capacity of 1159 mA h g(-1) at a 0.1 C rate, and retains a stable discharge capacity of 972 mA h g(-1) after 70 cycles and 845 mA h g(-1) after 120 cycles with a high Coulombic efficiency of over 99%. To our knowledge, this new methodology for lithium-sulfur cathodes has not been reported so far; the initial specific capacity is the highest value calculated based on total composite mass, which has not been disclosed in the literature.

Novel hierarchically porous carbon materials with very high surface areas, large pore volumes and high electron conductivities were prepared from silk cocoon by carbonization with KOH activation. The prepared novel porous carbon-encapsulated sulfur composites were fabricated by a simple melting process and used as cathodes for lithium sulfur batteries. Because of the large surface area and hierarchically porous structure of the carbon material, soluble polysulfide intermediates can be trapped within the cathode and the volume expansion can be alleviated effectively. Moreover, the electron transport properties of the carbon materials can provide an electron conductive network and promote the utilization rate of sulfur in cathode. The prepared carbon-sulfur composite exhibited a high specific capacity and excellent cycle stability. The results show a high initial discharge capacity of 1443 mAh g(-1) and retain 804 mAh g(-1) after 80 discharge/charge cycles at a rate of 0.5 C. A Coulombic efficiency retained up to 92% after 80 cycles. The prepared hierarchically porous carbon materials were proven to be an effective host matrix for sulfur encapsulation to improve the sulfur utilization rate and restrain the dissolution of polysulfides into lithium-sulfur battery electrolytes.

Novel sulfur-rich polymer composites were prepared from the commercial polysulfide rubber through facile vulcanization methods and were firstly used as cathode material for lithium/sulfur batteries. The sulfur enriched in the composites includes three parts, the first part was inserted into the main chains of the polysulfide rubber, the second part formed insoluble polysulfide (-S-n-)through self-polymerization and the third part was trapped inside the network of the above two polymer chains. The obtained sulfur-rich polymer composites have high sulfur content over 80%. Compared with the pure sulfur electrode, the composites showed better cycle stability and coulomb efficiency. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Novel polymeric materials with a very high content of sulfur were successfully synthesized via a facile copolymerization of elemental sulfur with 1,3-diethynylbenzene (DEB). For the as-prepared sulfur-rich polymeric materials (C-S copolymer), diynes or polydiynes are chemically cross-linked with a large amount of polymeric sulfur to form a cage-like semi-interpenetrating network (semi-IPN) structure. Due to the strong chemical interaction of sulfur with the carbon framework and the unique cage-like structure in C-S copolymers, the dissolution and diffusion of polysulfides out of the cathode is effectively suppressed through chemical and physical means. As a result, the sulfur-rich C-S polymeric materials with semi-IPN structure exhibit excellent cycling stability and high coulombic efficiency. The initial discharge capacity is 1143 mA h g(-1) at a 0.1 C rate. The capacity still remains at 70% even after about 500 cycles at a high current density of 1 C. In addition, a high coulombic efficiency of over 99% is obtained during the entire range of cycling.

Novel hierarchically porous carbon materials with very high surface areas, large pore volumes and high electron conductivities were prepared from silk cocoon by carbonization with KOH activation. The prepared novel porous carbon-encapsulated sulfur composites were fabricated by a simple melting process and used as cathodes for lithium sulfur batteries. Because of the large surface area and hierarchically porous structure of the carbon material, soluble polysulfide intermediates can be trapped within the cathode and the volume expansion can be alleviated effectively. Moreover, the electron transport properties of the carbon materials can provide an electron conductive network and promote the utilization rate of sulfur in cathode. The prepared carbon-sulfur composite exhibited a high specific capacity and excellent cycle stability. The results show a high initial discharge capacity of 1443 mAh g(-1) and retain 804 mAh g(-1) after 80 discharge/charge cycles at a rate of 0.5 C. A Coulombic efficiency retained up to 92% after 80 cycles. The prepared hierarchically porous carbon materials were proven to be an effective host matrix for sulfur encapsulation to improve the sulfur utilization rate and restrain the dissolution of polysulfides into lithium-sulfur battery electrolytes.

Novel polymeric materials with a very high content of sulfur were successfully synthesized via a facile copolymerization of elemental sulfur with 1,3-diethynylbenzene (DEB). For the as-prepared sulfur-rich polymeric materials (C-S copolymer), diynes or polydiynes are chemically cross-linked with a large amount of polymeric sulfur to form a cage-like semi-interpenetrating network (semi-IPN) structure. Due to the strong chemical interaction of sulfur with the carbon framework and the unique cage-like structure in C-S copolymers, the dissolution and diffusion of polysulfides out of the cathode is effectively suppressed through chemical and physical means. As a result, the sulfur-rich C-S polymeric materials with semi-IPN structure exhibit excellent cycling stability and high coulombic efficiency. The initial discharge capacity is 1143 mA h g(-1) at a 0.1 C rate. The capacity still remains at 70% even after about 500 cycles at a high current density of 1 C. In addition, a high coulombic efficiency of over 99% is obtained during the entire range of cycling.

Sulfur has a very high theoretical specific capacity of 1672 mA h g(-1) when used in lithium-sulfur batteries. However, the particularly rapid capacity reduction owing to the dissolution of intermediate polysulfide anions into the electrolyte still hinders practical application. In this respect, we report a novel core-shell structured sulfur-poly(sodium p-styrenesulfonate) (S@PSS) composite cathode material with a sulfur content as high as 93 wt% for lithium-sulfur batteries, which is the highest sulfur content disclosed in the literature. Due to the effective transport of lithium cations while blocking polysulfide anions by common ion Coulombic repulsion of the negatively charged -SO3- groups in the PSS protective layer, the S@PSS composite cathode exhibits a high initial specific capacity of 1159 mA h g(-1) at a 0.1 C rate, and retains a stable discharge capacity of 972 mA h g(-1) after 70 cycles and 845 mA h g(-1) after 120 cycles with a high Coulombic efficiency of over 99%. To our knowledge, this new methodology for lithium-sulfur cathodes has not been reported so far; the initial specific capacity is the highest value calculated based on total composite mass, which has not been disclosed in the literature.

Novel sulfur-rich polymer composites were prepared from the commercial polysulfide rubber through facile vulcanization methods and were firstly used as cathode material for lithium/sulfur batteries. The sulfur enriched in the composites includes three parts, the first part was inserted into the main chains of the polysulfide rubber, the second part formed insoluble polysulfide (-S-n-)through self-polymerization and the third part was trapped inside the network of the above two polymer chains. The obtained sulfur-rich polymer composites have high sulfur content over 80%. Compared with the pure sulfur electrode, the composites showed better cycle stability and coulomb efficiency. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Novel polymeric materials with a very high content of sulfur were successfully synthesized via a facile copolymerization of elemental sulfur with 1,3-diethynylbenzene (DEB). For the as-prepared sulfur-rich polymeric materials (C-S copolymer), diynes or polydiynes are chemically cross-linked with a large amount of polymeric sulfur to form a cage-like semi-interpenetrating network (semi-IPN) structure. Due to the strong chemical interaction of sulfur with the carbon framework and the unique cage-like structure in C-S copolymers, the dissolution and diffusion of polysulfides out of the cathode is effectively suppressed through chemical and physical means. As a result, the sulfur-rich C-S polymeric materials with semi-IPN structure exhibit excellent cycling stability and high coulombic efficiency. The initial discharge capacity is 1143 mA h g(-1) at a 0.1 C rate. The capacity still remains at 70% even after about 500 cycles at a high current density of 1 C. In addition, a high coulombic efficiency of over 99% is obtained during the entire range of cycling.

Sulfur has a very high theoretical specific capacity of 1672 mA h g(-1) when used in lithium-sulfur batteries. However, the particularly rapid capacity reduction owing to the dissolution of intermediate polysulfide anions into the electrolyte still hinders practical application. In this respect, we report a novel core-shell structured sulfur-poly(sodium p-styrenesulfonate) (S@PSS) composite cathode material with a sulfur content as high as 93 wt% for lithium-sulfur batteries, which is the highest sulfur content disclosed in the literature. Due to the effective transport of lithium cations while blocking polysulfide anions by common ion Coulombic repulsion of the negatively charged -SO3- groups in the PSS protective layer, the S@PSS composite cathode exhibits a high initial specific capacity of 1159 mA h g(-1) at a 0.1 C rate, and retains a stable discharge capacity of 972 mA h g(-1) after 70 cycles and 845 mA h g(-1) after 120 cycles with a high Coulombic efficiency of over 99%. To our knowledge, this new methodology for lithium-sulfur cathodes has not been reported so far; the initial specific capacity is the highest value calculated based on total composite mass, which has not been disclosed in the literature.

Novel sulfur-rich polymer composites were prepared from the commercial polysulfide rubber through facile vulcanization methods and were firstly used as cathode material for lithium/sulfur batteries. The sulfur enriched in the composites includes three parts, the first part was inserted into the main chains of the polysulfide rubber, the second part formed insoluble polysulfide (-S-n-)through self-polymerization and the third part was trapped inside the network of the above two polymer chains. The obtained sulfur-rich polymer composites have high sulfur content over 80%. Compared with the pure sulfur electrode, the composites showed better cycle stability and coulomb efficiency. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Novel hierarchically porous carbon materials with very high surface areas, large pore volumes and high electron conductivities were prepared from silk cocoon by carbonization with KOH activation. The prepared novel porous carbon-encapsulated sulfur composites were fabricated by a simple melting process and used as cathodes for lithium sulfur batteries. Because of the large surface area and hierarchically porous structure of the carbon material, soluble polysulfide intermediates can be trapped within the cathode and the volume expansion can be alleviated effectively. Moreover, the electron transport properties of the carbon materials can provide an electron conductive network and promote the utilization rate of sulfur in cathode. The prepared carbon-sulfur composite exhibited a high specific capacity and excellent cycle stability. The results show a high initial discharge capacity of 1443 mAh g(-1) and retain 804 mAh g(-1) after 80 discharge/charge cycles at a rate of 0.5 C. A Coulombic efficiency retained up to 92% after 80 cycles. The prepared hierarchically porous carbon materials were proven to be an effective host matrix for sulfur encapsulation to improve the sulfur utilization rate and restrain the dissolution of polysulfides into lithium-sulfur battery electrolytes.