Spray pyrolysis of yolk–shell particles and their use for anodes in lithium-ion batteries

• Spray pyrolysis is compatible with the production of yolk–shell structure.
• We demonstrate this for the case of nickel oxide (shell)–silicon (yolk) particles.
• After annealing, these particles can be used as anodes for lithium-ion batteries.
• Performance: 1400 mAh/g at 0.5 C for 100 cycles

We demonstrate the synthesis of yolk–shell particles using spray-pyrolysis, a technique with proven scalability to industrial production level. Nickel oxide (shell)–silicon (yolk) particles are produced using a single-step aerosol reaction from a mixture of commercial, off-the-shelf precursors. After coating and annealing in the presence of polyvinylpyrrolidone, the nickel oxide shell is converted into a porous nickel cage enclosing the silicon particles. The polymer decomposition leads to the formation of an amorphous carbon layer surrounding the nickel cage. This structure maintains a high specific discharge capacity after more than 100 cycles (~ 1400 mAh/g at the 110th cycle with a 0.5 C discharge rate, on a silicon basis) when used as anode for lithium-ion batteries.