Atomic tuning of titanium-chromium nitride catalysts unlocks high-performance lithium-sulfur batteries

As fossil fuels continue to deplete and environmental pollution intensifies, the development and application of clean energy have garnered widespread attention. Lithium-sulfur (Li-S) batteries, with their remarkable theoretical specific capacity of 1675 mAh g^-1 and energy density of 2600 Wh kg^-1, which is about six times that of conventional lithium-ion batteries at 387 Wh kg^-1. Additionally, they offer advantages including environmental sustainability, high safety, and low cost, making them a highly promising solution for future electrochemical energy storage.

 

A research team led by Professor Jie Sun at Shaanxi Normal University has announced a major breakthrough in lithium-sulfur (Li-S) battery technology. Through atomic-level precision engineering, the team has developed a novel titanium-chromium nitride (Ti_xCr_1-xN) solid-solution catalyst that efficiently traps and rapidly converts polysulfides, which is the key culprit behind the short lifespan and poor efficiency of Li-S batteries. This innovation effectively addresses a fundamental barrier to the practical application of this high-energy-density technology.

 

The team published their article in Nano Research on April 22, 2025.

 

“The core innovation of this battery material research lies in our achievement of 'precision tuning' of the material’s electronic structure through continuous adjustment of the composition in Ti_xCr_1-xN solid-solution at atomic scale. This is not merely a simple material mixture, but a true form of solid-solution phase with atomic-level interface engineering,” stated Professor Jie Sun, the corresponding author of the paper from the School of Materials Science and Engineering at Shaanxi Normal University.

 

Transition metal compounds leverage the “Lewis’s acid-base” interaction between metal ions and polysulfide anions to achieve strong chemical adsorption. Simultaneously, the d-orbitals of transition metals can couple with the frontier orbitals of polysulfide anions, facilitating electron transfer and enhancing polysulfide conversion efficiency. Among them, transition metal nitrides exhibit exceptional physicochemical stability and high electrical conductivity due to their stable metal lattice structure and nitrogen interstitial alloying effects, demonstrating potential as ideal sulfur host materials. These combined properties establish metal nitrides as promising candidate materials for lithium-sulfur battery cathodes.

 

The research team synthesized flexible CNFs@TCN membranes using electrospinning and high-temperature nitridation methods. By varying the ratio of titanium and chromium precursors, they were able to continuously modulate the electronic structure of the resulting solid-solution material. This atomic-level electronic fine-tuning directly determines the material’s key properties.

 

Both theoretical calculations and experimental results confirm that when the Ti/Cr atomic ratio reaches 1:2, the d-band center of the catalyst is optimally positioned. This configuration significantly enhances the adsorption energy for polysulfides compared to pure TiN or CrN, while providing an optimal pathway for charge transfer. As a result, the dual functions of “trapping” and “conversion” are synergistically strengthened, fundamentally addressing both the shuttle effect and slow reaction kinetics in Li-S batteries.

 

The Li-S battery assembled with this material demonstrates a significant electrochemical breakthrough. The CNFs@TCN-1/2 electrode delivers a high specific capacity of 801 mAh g^-1 and maintains 93% of its capacity after 600 cycles at 2 C, with an ultralow decay rate of only 0.012% per cycle. These results strongly validate the exceptional stability and effectiveness of the catalyst in suppressing the shuttle effect and enhancing conversion efficiency.

 

Looking ahead, Professor Sun concluded, “This work demonstrates that atomic-level doping via solid-solution construction is a powerful strategy for regulating the catalytic performance of transition metal nitrides. It opens new avenues for designing highly efficient catalysts for complex multi-step reactions, extending beyond Li-S batteries to other energy conversion and storage fields.”

 

Other contributors include Jiyuan Zhang, Weiye Zhang, Jiarui Xue, Nan Zhu, Yunping Ge, Zhibin Lei, Qi Li, Xuexia He, and Zonghuai Liu from the Key Laboratory of Applied Surface and Colloid Chemistry at Shaanxi Normal University.

 

This work was funded by the Natural Science Basic Research Plan of Shaanxi Province (2025JC-YBMS-351, 2019JLP-12), the funds of Shaanxi Sanqin Scholars Innovation Team, and the Central University Foundation of Shaanxi Normal University (GK202302005).

 

About Nano Research

Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.

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