Battery Buffer Takes the Strain
July 30, 2015 | CASEstimated reading time: 1 minute
Researchers in China and the US have developed a layered oxide that shrinks when ions are intercalated into it, with the hope of buffering the volume expansion seen in common electrode materials.
Layered oxide materials are very stable, contain large interstitial spaces, and often undergo a volume change, or “strain effect”, when ions are incorporated into their structure. This volume change is detrimental to the electrode as it often results in inferior long-term cycling stability and reduced battery safety. So-called zero-strain materials, where no volume change is seen, are ideal electrode materials. However, these are very rare and most layered oxides exhibit a positive strain effect.
Many layered oxides have the formula AxMO2, and consist of stacked (MO2)n sheets with edge-sharing MO6 octahedra, in between which alkali metal atoms are located at octahedral, tetrahedral, and prismatic sites. Now, Xuefeng Wang at the Chinese Academy of Sciences and co-workers have synthesised Na0.5NbO2, a layered oxide in which the NbO6 clusters are edge-sharing trigonal prisms rather than octahedra. In this structure the sodium and niobium ions are positioned contrary to conventional layered materials.
Na0.5NbO2 is a rare negative-strain material with high stability, a long cycling life and an impressive rate performance. As Jang Wook Choi, a researcher in the Energy Nanomaterials Group at the Korea Advanced Institute of Science and Technology explains, ‘this is opposite to other cases or common sense, as the volume shrinks even after you put something inside the structure.’ The negative volume effect appears to be a result of enhanced interlayer Na–O interactions and weakened Nb–Nb and Nb–O bonding on sodium intercalation.
Wang and colleagues evaluated Na0.5NbO2 both as an independent electrode material, and as a buffer in composite electrodes with positive-strain materials, in which it counteracts the volume expansion caused by a positive strain effect. The material had a more significant volume effect than other volume buffer materials, as well as being electrically conductive and compatible with electrolytes at the required voltage.
'The limitation of our system lies in the high cost of niobium and the difficulty of synthesis,’ says Wang. ‘But we think that these results will influence the thinking about layered structures and how to design a better electrode for rechargeable batteries.’ (Royal Society of Chemistry)
Suggested Items
LQDX Divests Aluminum Soldering Business - Mina™ - to Taiyo America Inc.
05/02/2024 | PRNewswireLQDX, formerly known as Averatek Corp., developer of high-performance materials for advanced semiconductor manufacturing, today announced that it has divested its aluminum soldering business – known as MinaTM – to Taiyo America Inc., a global market leader in advanced electronic materials.
Indium Corporation Expert to Present on Pb-Free Solder for Die-Attach in Discrete Power Applications
04/30/2024 | Indium CorporationIndium Corporation Product Manager – Semiconductor Dean Payne will present at the Advanced Packaging for Power Electronics conference, hosted by IMAPS, held May 8-9 in Woburn, Massachusetts, USA.
Real Time with... IPC APEX EXPO 2024: Adhesive Materials and Equipment Update with Dymax
05/01/2024 | Real Time with...IPC APEX EXPOVirginia Hogan, global business development manager at Dymax, discusses adhesive materials, dispensing and curing equipment, a new, high-reliability conformal coating, and various materials and dispensing methods.
Real Time with... IPC APEX EXPO 2024: Sustainability in the Industry
04/26/2024 | Real Time with...IPC APEX EXPOGuest Editor Henry Crandall and Chris Nash of Indium Corporation discuss the company's 90th anniversary and its focus on sustainability. They focus on the benefits of sustainable materials, their compatibility, and value propositions. The conversation also highlights how Durafuse LT technology's role in reducing reflow temperatures is leading to significant cost and energy savings. Nash also touches on downstream sustainability efforts such as using recycled materials for packaging.
SMC Korea 2024 to Highlight Semiconductor Materials Trends and Innovations on Industry’s Path to $1 Trillion
04/24/2024 | SEMIWith Korea a major consumer of semiconductor materials and advanced materials a key driver of innovation on the industry’s path to $1 trillion, industry leaders and experts will gather at SMC (Strategic Materials Conference) Korea 2024 on May 29 at the Suwon Convention Center in Gyeonggi-do, South Korea to provide insights into the latest materials developments and trends. Registration is open.