"aim of which" is a correct phrase and can be used in written English.
It is typically used to introduce the purpose or goal of something previously mentioned in the sentence. Example: The company launched a new marketing campaign, the aim of which was to increase their global sales by 25%.
The government will have to state its clear strategic aim – of which we have heard precious little of late.
It is a primitive bodily response, the aim of which is to ensure the survival of our DNA.
The aim of which is to develop opportunities for young learners to have a more emotional connection with their learning material.
More recently, there was a popular blog called birminghamitsnotshit.co.uk, the aim of which was to offer a counter-narrative to those who believed otherwise.
The division was created as part of Ofgem's restructuring the aim of which is to increase Ofgem's role in helping to meet Britain's targets to cut carbon emissions.
It matters when a government minister leads a highly emotional internet campaign, the aim of which is to get a writer, and the person who commissioned her, fired.
This is the "third arrow" of Mr Abe's economic programme, known as Abenomics, the aim of which is to revive Japan's economy.
A magistrate authorized special units of the Belgian federal police to "work out an infiltration operation, the aim of which was to detain Afweyne".
He is also suspicious of the steam-cleaning business, the aim of which, he says, is just to avoid the cost of vitrification.
A PAC military organization, Poqo (Xhosa: "Pure"), was formed, the aim of which was to overthrow white rule in South Africa by violence.
Money market, a set of institutions, conventions, and practices, the aim of which is to facilitate the lending and borrowing of money on a short-term basis.
